AARoads:United States/Montana/All-time list

Given are the years of the first and last official maps (also [1] is a little blurry but has a few that aren't on the MDT site) the routes appear on. These are not always the exact years the routes were created or eliminated.

A 1927 and 1930 map and a 1929 map show an almost completely different numbering system.

A 1932 Gousha/Conoco map shows some routes; these are marked with an asterisk. Note that all except 22 (which was kept in the numbering system) were odd.

Secondary routes first appear on maps in 1960, but federal aid logs are available back to 1938 (1943 is the first with secondaries) (post-1993 logs). Therefore all secondary years are based on the logs, but primary years are based on maps.

haven't gone through these: 2011 log 2013 log

	from	to	notes
MT 1	1987 ← US 10A	now
MT 1	1936 ← 191	1958 → 287 (part)	1 may have been skipped in the original numbering
MT 2	1987 ← US 10 (part)	now	parts are not state maintained 2 was skipped in 1934 because of US 2
MT 3	1957	now
MT 3	1931 ← 33 (part)	1940 → US 10A	numbered to match Idaho
MT 4	1931?	1938	Idaho to Thompson Falls; now 471 numbered to match Idaho
MT 5	1931 ← 17	now	numbered to match North Dakota
MT 6	1931? ← 33 (part)	1959 → US 12 (part)
MT 7	1931 ← 10 (part)	now
MT 8	1934	1961 → US 212 (part)
MT 9	1931 ← 91	1938	Idaho to Lolo; became 412 in 1947 numbered to match Idaho
MT 10	1927	1931 → 7
MT 10	when?	now?
MT 11	1927	1931 → US 12 (part)	portion removed in 1930 was US 10 west of Miles City and US 12 east of Ismay
MT 11	1931 ← 76	1932 → US 91 (part)
MT 11	1936	when?	where? was one of the unlabeled roads
MT 12	1927	1931 → 15
MT 13	1934	now	unlabeled road in 1929
MT 13W	1954 ← 13 (part)	1993 → 25
MT 14	1927	1953 → 16 (part), 23N	portion removed in 1930 was US 10 from Miles City to Glendive
MT 15	1931 ← 12	1938	Stanford to Chester; now 80, 223
MT 16	1927	now
MT 17	1927	1931 → 5
MT 17	1931 ← 20	1932	Redstone to Canada
MT 17	1936	now	not state maintained since 1963
MT 18	1927	1931	Sidney via Girard and Poplar to Scobey; now 201 and county roads
MT 18	1934 ← 55	1958 → 20 (part), 20S
MT 19	1963 ← 191	now
MT 19	1931 ← 32	1962 → US 191 (part)
MT 20	1927	1931 → 17	Redstone to Canada
MT 20	1931 ← 33 (part), 69	1967 → 200
MT 20S	1959 ← 18 (part)	1967 → 200S
MT 21	1949	now
MT 21	1931	1938	Columbus to Ryegate; now 300, 306
MT 22	1927	1985 → 59 (part)	part of original numbering system; retained
MT 23	1931	now	numbered to match North Dakota disappeared in 1948; part of 16 in 1950; returned in 1951 mainline 23 became part of 20 in 1959, but 23S became 23 in 1960
MT 23N	1954 ← 14 (part)	1959 → 20 (part)
MT 23S	1954 ← 23 (part)	1959 → 23
MT 24	1949 ← 22 (part)	now
MT 24	1931 ← 77	1938	Jennings (Libby Dam) to Marion
MT 24W	1978 ← 24 (part)	1993 → 42
MT 25	1994 ← 13W	now
MT 25	1931 ← 30	1938	Billings to Lewistown; now 3, 238 (part)
MT 26	1931	1938	Trout Creek to Manicke
MT 27	1931 ← 34	1938	Winifred to Big Sandy; now 236
MT 28	1931	now
MT 29	1931 ← 68	1947 → US 87 (part)	1956 shows 29 on current 324, but that's probably simply the shield being on the wrong side of the border
MT 30	1927	1931 → 25	old route removed in 1930 and was concurrent with US 87E (south of Grassrange only)
MT 30	1931 ← 10 (part)	1938	Miles City to South Dakota via Ekalaka
MT 31	1931 ← 86 (part)	1938	Bigfork to Drummond; now 83, 141, 200, 271
MT 32	1927	1931 → 19
MT 32	1931 ← 42	1938 → US 12 (part)
MT 33	1927	1931 → 3, 6, 20
MT 33	1931 ← 88	1958 → 287 (part)
MT 34	1927	1931 → 27
MT 34	1931 ← 71	1961 → 287 (part)
MT 35	1927	1931	Helena to White Sulphur Springs; now Canyon Ferry Road, 284, Confederate Gulch Road, Benton Gulch Road, and 360
MT 35	1931 ← 92	now	disappeared in 1939, but returned in 1951 (had been 210)
MT 36	1931 ← 90	1938	Lost Trail Pass to Dillon; now 43, 278
MT 37	1931 ← 94	now
MT 38	1931 ← 87	now	not state maintained since 1975-1976
MT 39	1931	1938 → 19 (part)	Hysham to Canada via Malta; now US 191, 245
MT 39	1978 ← 315	now	numbered the same as its federal aid number (assigned 1976)
MT 40	1927	1930 → US 310
MT 40	1936	now	Became part of 37 in 1939-40 but became 40 again in 1947-48; unlabeled until 1949
MT 41	1931 ← 72	now
MT 42	1927	1931 → 32
MT 42	1936	when?	where? was one of the unlabeled roads
MT 42	1994 ← 24W	now
MT 43	1931 ← 86 (part)	now	disappeared in 1939, but returned in 1949
MT 44	1936	when?	where? was one of the unlabeled roads
MT 44	1978 ← 216	now	numbered the same as its federal aid number (assigned 1976)
MT 45	1931 ← 57	1938	Lame Deer to Forsyth; now 39 (part), 447
MT 46	1936	when?	where? was one of the unlabeled roads
MT 47	1934	now	disappeared in 1939, but returned in 1948
MT 48	1936	now	unlabeled until 1949
MT 49	1936	1936 → 41 (part)	41 followed current 55 at the time
MT 49	1940	now	unlabeled until 1949; swapped with US 2 in 1950-1951 not state maintained since 1975-1976
MT 50	1936	1953 → 13 (part)	east of Wolf Point; unlabeled until 1953
MT 50	1966 ← 287 (part)	1967 → 87
MT 55	1927	1931 → 18	sections to the west and east replaced by US 87E and US 10
MT 55	1978 ← 287 (part)	now	numbered the same as its federal aid number (assigned 1976)
MT 56	1978 ← 202	now	numbered the same as its federal aid number (assigned 1976)
MT 57	1927	1931 → 45
MT 59	1967 ← 319	now	numbered to match Wyoming
MT 60	1927	1931 → 187
MT 61	1927	1931	Brady to Carter; now partially 564
MT 62	1927	1931	Watson to Ulm; now 360
MT 63	1927	1931	Conrad to north of Dupuyer; now 534
MT 64	1981	now	numbered the same as its federal aid number (assigned 1976 from former P-50 Spur)
MT 66	1927	1930 → US 87W, US 87
MT 66	1978 ← 376	now	numbered the same as its federal aid number (assigned 1976)
MT 68	1927	1931 → 29	Section southwest to Wolf Creek was removed in 1930 and was concurrent with US 91
MT 68	2001?	now	unlabeled at first; color changes to red in 2001 numbered the same as its federal aid number (assigned 1976)
MT 69	1927	1931 → 20 (part)
MT 69	1978 ← 281	now	numbered the same as its federal aid number (assigned 1976)
MT 70	1927	1931 → 191
MT 71	1927	1931 → 34
MT 72	1927	1931 → 41
MT 72	1978 ← 308 (part), 397	now	numbered the same as its federal aid number (assigned 1976)
MT 76	1927	1931 → 11
MT 77	1927	1931 → 24	Original route was councurrent with US 2; rerouted in 1929 and section concurrent with US 2 removed 1930
MT 78	1978 ← 307	now	numbered the same as its federal aid number (assigned 1976)
MT 80	1978 ← 230	now	numbered the same as its federal aid number (assigned 1976)
MT 81	1978 ← 235	now	numbered the same as its federal aid number (assigned 1976)
MT 82	1978 ← 208	now	numbered the same as its federal aid number (assigned 1976)
MT 83	1978 ← 209 (part), 326	now	numbered the same as its federal aid number (assigned 1976)
MT 84	1978 ← 289	now	numbered the same as its federal aid number (assigned 1976)
MT 85	1978 ← 291 (part)	now	numbered the same as its federal aid number (assigned 1976)
MT 86	1927	1931 → 31, 110, 43
MT 86	1978 ← 293	now	numbered the same as its federal aid number (assigned 1976)
MT 87	1927	1931 → 38
MT 87	1968 ← 50	now
MT 88	1927	1931 → 33
MT 90	1927	1931 → 36	Section north of there was concurrent with US 93 and was removed in 1930
MT 91	1927	1931 → 9
MT 92	1927	1931 → 35
MT 94	1927	1931 → 37
MT 110	1931 ← 86 (part)	1936 → US 10A	now 1
MT 117	1978 ← 249	now	numbered from its federal aid number P-17 (assigned 1976)
MT 135	1978 ← 461	now	numbered from its federal aid number P-35 (assigned 1976)
MT 141	1978 ← 271 (part), 272	now	numbered from its federal aid number P-41 (assigned 1976)
MT 187	1931 ← 60	1938	mostly became US 191 in 1934-1935; rest is now 86
MT 191	1961	1962 → 19
MT 191	1931 ← 70	1935 → 1
MT 200	1968 ← 20	now
MT 200S	1968 ← 20S	now
S-201	1952	now	maintained (but not signed) as a primary route east of MT 16
S-202	1977	now
S-202	1945	1975 → 56
S-203	1952	now
S-204	1952	now
S-205	1976 ← US 10 (part)	now
S-205	1943	1945	north from Plains
S-206	1943	now	swapped with US 2 in 1981-1983
S-207	1978	now
S-207	1943	1975	Southeast from Kalispell
S-208	1978	now
S-208	1943	1975 → 82
S-209	1945	now
S-210	1976 ← US 10-12 (part)	now
S-210	1943	1950 → 35
S-211	1943	now
S-212	1943	now
S-213	1943	now
S-214	1943	now	originally west from Sweetgrass, but gradually moved to west from Sunburst and original route became part of 213, then moved back in 1975-1976 when 213 replaced 483
S-215	1943	now
S-216	1981	1993	279 to Marysville
S-216	1943	1975 → 44
S-217	1976 ← 343 (part)	now
S-217	1943	1945	became 534 in 1964
S-218	1945	now
S-219	1943	now
S-220	1943	now
S-221	1943	now
S-222	1976 ← US 91 (part)	now
S-222	1943	1945	became 431 in 1955
S-223	1943	now
S-224	1943	now
S-225	1943	now
S-226	1943	now
S-227	1943	now
S-228	1945	now
S-229	1976 ← US 91 (part)	now
S-229	1943	1954 → 223 (part)	northwest from Fort Benton
S-230	1982	1993	unbuilt north frontage road, east of Laurel to 40th Street Billings
S-230	1945	1975 → 80
S-231	1983	now
S-231	1943	1975	became 255 in 1984
S-232	1943	now
S-233	1943	now
S-234	1943	now
S-235	1983	now
S-235	1943	1975 → 81
S-236	1943	now
S-237	1943	now
S-238	1943	now
S-239	1943	now
S-240	1943	now
S-241	1943	now
S-242	1943	1993 → US 191 (part)
S-243	1943	now
S-244	1943	now
S-245	1943	now
S-246	1943	now
S-247	1983	now	typoed as 246 in 1983 log
S-247	1943	1975 → 24 (part)	listed as being part of MT 22 in 1943
S-248	1943	now
S-249	1984	now
S-249	1943	1975 → 117
S-250	1943	now
S-251	1943	now
S-252	1943	now
S-253	1943	now
S-254	1943	now
S-255	1984	now	had been 231 until 1975-1976
S-255	1943	1945	Outlook to Raymond
S-256	1943	1975 → 16 (part)	listed as being part of MT 16 in 1943 was this number reused in 1984?
S-257	1952	now
S-258	1943	now
S-259	1984	now
S-259	1943	1954 → 201 (part)	west from Fairview
S-260	1986	now	had been 506 until 1975-1976
S-260	1943	1950 → 23 (part)	Lambert to Sidney
S-261	1943	now
S-262	1943	1975	Southside Road, northwest from Superior
S-263	1943	now
S-264	1943	1974 → FAU 8102	3rd Street and Clements Road, Higgins Avenue to South Avenue, Missoula
S-265	1943	1974 → FAU 8120	South Avenue, Higgins Avenue to Clements Road, Missoula
S-266	1943	1974 → FAU 8117	Higgins Avenue, Russell Street to Brooks Street, Missoula
S-267	1943	1993	Van Buren Street and Rattlesnake Drive, northeast from Missoula disappeared in 1976, but reappeared in 1978
S-268	1943	1975 → 203 (part)
S-269	1943	now
S-270	1953	1993	323 to Capitol
S-271	1945	now
S-272	1987	now	why this number? missing from current state map
S-272	1945	1975 → 141 (part)
S-273	1943	now
S-274	1943	1985	became 569 in 2001
S-275	1987	now	why this number?
S-275	1943	1975	Stewart Street, east of Anaconda
S-276	1943	now
S-277	1953	now
S-278	1943	now
S-279	1943	now
S-280	1943	now
S-281	1943	1975 → 69
S-282	1987	now	why this number?
S-282	1943	1945 → 41 (part)	41 and Burma Road southwest from Twin Bridges
S-283	1943	now
S-284	1943	now
S-285	1943	now
S-286	1943	now
MT 287	1959 ← 1, 33	now
MT 287A	1962 ← 287 (part)	1965 → US 287
S-287	1943	now
S-288	1943	now
S-289	1943	1975 → 84
S-290	1943	now
S-291	1943	2001	south from Belgrade; mostly became 85 in 1975-1976
S-292	1996	now	why this number?
S-292	1953	1975	Ekalaka to Mill Iron
S-293	1945	1975 → 86
S-294	1943	now
S-295	1943	now
S-296	1943	1975	south from Two Dot
S-297	1943	now
S-298	1943	now
S-299	1943	1975 → 238 (part)
S-300	1943	now
S-301	1943	1956 → 3
S-302	1943	now
S-303	1943	1975	8th Road?, I Road, and Fly Creek Road, Huntley to Nibbe
S-304	1943	1975	Shepherd Road, old US 312 to Scandia Road, northwest of Huntley
S-305	1943	1975 → 532 (part)	72nd Street and King Avenue (532), Laurel to Billings
S-306	1945	now
S-307	1943	1975 → 78
S-308	1943	now
S-309	1943	1972	northwest from Roundup
S-310	1943	now
S-311	1943	now
S-312	1943	1962	Gumbo Hill Road, southeast from Hysham north end became part of P-2, carrying US 10-312 (at least until I-94 was built east of Hysham); now part of 311
S-313	1943	now
S-314	1946	now
S-315	1943	1975 → 39
S-316	1943	1945	became 446 in 1956
S-317	1953	now
S-318	1953	1974 → FAU 1014	Airport Road, Billings
S-319	1943	1966 → 59
S-320	1943	now
S-321	1943	1975	northeast from Plevna
S-322	1943	now
S-323	1943	now
S-324	1945	now
S-325	1946	now
S-326	1990	now	why this number? had been 492 until 1975-1976
S-326	1954	1975 → 83 (part)
S-327	1953	now
S-328	1994	now	why this number?
S-328	1953	1975	Acton to Broadview
S-329	1953	1975	Duck Creek Road, east of Laurel
S-330	1945	now
S-331	1945	now
S-332	1945	now
S-333	1945	1983	east of Miles City
S-334	1994	now	why this number?
S-334	1945	1962 → 13 (part)	north from Scobey
S-335	1945	now
S-336	1945	now
S-337	1956	1957	Basin Creek Road, west from Volborg
S-338	1954	now
S-339	1954	1975	northeast from Wilsall
S-340	1954	now
S-341	1954	now
S-342	1954	now	missing from the current state map
S-343	1954	now
S-344	1954	now
S-345	1946	now
S-346	1946	now
S-347	1945	now
S-348	1945	now
S-349	1954	1975	Plentywood to Comertown
S-350	1954	now
S-351	1945	1954 → 236 (part)	southeast from Big Sandy
S-352	1945	now
S-353	1945	1975	northwest from Moiese
S-354	1945	now
S-355	1954	1974 → FAU 5802	Custer Avenue, Montana Avenue to Henderson Street, Helena
S-356	1945	1975	Williams Street and Birdseye Road, northwest from Helena
S-357	1945	now
S-358	1954	now
S-359	1945	now
S-360	1945	now
S-361	1975	1983	Melrose to Twin Bridges
S-361	1945	1947 → 209 (part)	northwest from 20
S-362	1945	1975	became 571 in 2001
S-363	1945	now
S-364	1945	1975	south from Malta
S-365	1945	now
S-366	1945	now
S-367	1945	1975	northeast of Corvallis
S-368	1945	1975	east from Hamilton
S-369	1954	1975	east of Conrad
S-370	1945	now
S-371	1954	1975	west from Melville
S-372	1945	1975	east from Stevensville
S-373	1945	now
S-374	1945	now
S-375	1954	1993	Continental Drive, Butte (where was the north end pre-1974?)
S-376	1956	1975 → 66
S-377	1955	1975	southeast of Stevensville
S-378	1945	1975 → 220 (part)
S-379	1945	now
S-380	1955	1975	northeast of Hamilton
S-381	1945	now	disappeared in 1976, but returned in 1979
S-382	1945	now
S-383	1955	1975	southeast of Hamilton
S-384	1945	now
S-385	1945	1975	west of Highwood
S-386	1945	now
S-387	1945	now
S-388	1955	1975	southeast of Hamilton
S-389	1945	1975	southeast of Cut Bank
S-390	1945	1974 → FAU 8109	39th Street and Russell Street, Brooks Street to Broadway Street, Missoula
S-391	1945	now
S-392	1946	1963	Butte Municipal Airport entrance from Harrison Avenue (US 10)
S-393	1945	now
S-394	1945	1975	south from Shawmut
S-395	1946	1962	30th Street and Poly Drive, Montana Avenue to 17th Street, Billings
S-396	1946	now
S-397	1945	1975 → 72 (part)
S-398	2000	now	why this number? had been 402 until 1985-1987
S-398	1946	1956 → 273 (part)	east of Anaconda
S-399	1946	now	disappeared in 1976, but returned in 1993
S-400	1946	now
S-401	1987	now	why this number?
S-401	1946	1975 → 55	southwest from Whitehall signed as part of 287 from 1961 to 1967
S-402	1946	1985	became 398 in 2000
S-403	1946	1974 → FAU 1801	Main Street, Daly Street, Walkerville Drive, and Excelsior Avenue, Park Street to Hornet Street?, Butte-Walkerville
S-404	1946	1975 → 344 (part)
S-405	1946	now
S-406	1946	1965 → 405 (part)	east from Froid
S-407	1946	1975	Beck Hill Road, north of Deer Lodge
S-408	1946	now
S-409	1946	now
S-410	1955	1975 → 343 (part)
S-411	1946	now
S-412	1995	now	numbered as spur of 411
S-412	1947	1975 → US 12	west from Lolo; became P-93 in 1976
S-413	1948	now
S-414	1948	1975	south from St. Phillip
S-415	1950	1975 → 384 (part)
S-416	1950	now
S-417	1950	now
S-418	2000	now	numbered as spur of 416
S-418	1951	1975	southwest from Wyola
S-419	1951	now
S-420	1951	now
S-421	1951	now
S-422	1951	now
S-423	1951	1975	German Gulch Road, west of Butte
S-424	1951	now
S-425	1951	1975	southwest from Fishtail
S-426	1951	now
S-427	1951	now
S-428	2001	2001	a bit of the I-90 south frontage road east from Wise Lane, Billings only appears in 2001 log (which erroneously says it comes from 1952), but the 1999 log is missing
S-428	1952	1977 → 297 (part)	east from Judith Gap
S-429	1952	2001	I-90 south frontage road, Wise Lane, and 40th Street West, Elysian Road to Rimrock Road, Billings mostly removed in 1997-2001
S-430	1987	now	why this number?
S-430	1955	1980 → FAU 8103	Reserve Street, Missoula; now US 93
S-431	1955	now	had been 222 in the 1940s
S-432	1955	now
S-433	1955	1975	Wylie Drive, east of Helena
S-434	1955	now
S-435	1987 ← 434 (part)	now
S-435	1955	1975	northwest from Augusta
S-436	1955	1975	northeast from Zurich
S-437	1956	now
S-438	1955	now
S-439	never?	never?	was this number skipped?
S-440	1956	1975	Beef Trail Road and Little Basin Creek Road, southwest from Butte
S-441	1956	now
S-442	never?	never?	was this number skipped?
S-443	never?	never?	was this number skipped?
S-444	1956	now
S-445	1956	1975	northwest from Browning
S-446	1956	now	had been 316 in the 1940s
S-447	1956	now
S-448	1955	now
S-449	1955	now
S-450	1955	1975	south from Kremlin
S-451	1988 ← US 87 (part)	now	why this number?
S-451	1955	1960 → 448 (part)	west from Box Elder
S-452	1955	1975	southeast from Havre
S-453	1956	now
S-454	1956	now
S-455	1956	1956 → 310 (part)	northwest from Custer
S-456	1956	1975	Lodgepole Road, west of Whitefish
S-457	1988 ← P-74	now	why this number?
S-457	1956	1970 → 366 (part)	across Tiber Dam
S-458	1956	1975 → 345 (part)	19th Avenue, south from Bozeman
S-459	1956	1993	13th Street, 10th Avenue South to 226, south from Great Falls
S-460	1956	1975	south from Gold Creek
S-461	1956	1975 → 135
S-462	1956	now
S-463	1957	now
S-464	1957	now
S-465	1956	1975	north from Van Norman
S-466	1956	now	disappeared in 1976, but returned in 1978
S-467	1957	now
S-468	1957	1958 → 254 (part)	northwest from Richey
S-469	1957	1985	north of Fairview
S-470	1957	now
S-471	1957	now	had been 4 until 1938-1939
S-472	1993	now	why this number?
S-472	1957	1975	northeast from Sula
S-473	1957	now
S-474	1957	now
S-475	1957	1975 → 295 (part)	east of Livingston
S-476	1957	1975	southeast from Pray
S-477	1957	1975	west from Red Lodge
S-478	1957	now
S-479	1957	1975	north of Big Timber
S-480	1957	now
S-481	1957	1975	Old Highway 282, southeast of Helena (was this actually part of 282?)
S-482	1958	now
S-483	1958	1975 → 213 (part)
S-484	1958	now
S-485	1959	1975	southwest of Broadus
S-486	1958	now
S-487	1958	now
S-488	1959	1981	east of Sidney
S-489	1959	now	disappeared in 1976, but returned in 1985
S-490	1959	1975	east from Conner
S-491	never?	never?	was this number skipped?
S-492	1959	1975	became 326 in 1990
S-493	1959	now
S-494	1959	now
S-495	1959	1975	25th Avenue, Rainbow Dam Road, and Morony Dam Road, Old Havre Highway to US 87, north of Great Falls
S-496	1959	1975	northeast of Culbertson
S-497	1959	1975	northwest from Harlowton
S-498	1959	1974 → FAU 5205	River Drive and 57th Street, 9th Street to 10th Avenue South, Great Falls (mileage is off - 4.5 may be a typo)
S-499	1959	1975 → US 287 (part)	had been part of 287 until 1959 Yellowstone earthquake signed as part of US 287 from 1965; became P-87 in 1976
S-500	1960	now
S-501	1960	1975	south of Grantsdale
S-502	1960	1975	56th Street, I-90 to King Avenue, west of Billings
S-503	1960	now
S-504	1960	now
S-505	1960	1980 → 426 (part)
S-506	1961	1975	became 260 in 1986
S-507	1961	now
S-508	1961	now
S-509	1961	now
S-510	1961	1999	east from Brockway 1999 log not available, but it's on the 1999 map
S-511	1962 ← 13 (part)	now
S-512	1962	now
S-513	1962	now
S-514	1962	1975	north from Poplar
S-515	1991	2001	southwest from Plentywood on the 2001 map but not the 2001 log why this number?
S-515	1961	1975	became 573 in 2001
S-516	1961	now
S-517	1961	now
S-518	1961	now
S-519	1962	1978	northeast of Roundup
S-520	1962 ← US 10 (part)	1975	west from Cyr
S-521	1962	1972	Northwest Bypass, Great Falls became part of FAP 3 at first, but in 1974 it became FAU 5206
S-522	1962	now
S-523	1963 ← US 2 (part)	1975 → 241 (part)	through Harlem
S-524	1962	1975	Rocky Point Road, northwest of Polson
S-525	1962	1975	Finley Point Road, northeast of Polson
S-526	1963	1975	north from Logan
S-527	1963	1975	southwest of Cameron
S-528	1963	now	disappeared in 1976, but returned in 1998
S-529	1963	now
S-530	1963	1975	east from Ronan
S-531	1963	now
S-532	1964	now
S-533	1965	2005?	Pattee Canyon Drive and Deer Creek Road, east of Missoula in 2005 log but not 2005 traffic counts (it is in the 2004 traffic counts)
S-534	1964	now	had been 217 in the 1940s
S-535	1964	1974 → FAU 1004, FAU 1018	Grand Avenue and 6th Avenue North, Shiloh Road to US 87, Billings
S-536	1964	1993	Griffin Drive, Bozeman
S-537	1965	now
S-538	1965	1974 → FAU 1810	Grand Avenue, Harrison Avenue to Continental Drive, Butte
S-539	1965	1975	Hauser Street, east of Anaconda
S-540	1966	now
S-541	1966	now
S-542	1967	1975	became 572 in 2001
S-543	1967	now
S-544	1968	now
S-545	1968	1974 → FAU 1203	Lincoln Street and 11th/10th Avenue, 19th Avenue to Main Street, Bozeman
S-546	1968	1975 → 322 (part)	northeast of Ekalaka
S-547	1969	now
S-548	1969	now
S-549	1970	1993	east from Whitehall
S-550	never?	never?	was this number skipped?
S-551	1971	now
S-552	1973	now
S-553	never?	never?	was this number skipped?
S-554	1971	1975	northeast from Winston
S-555	never?	never?	was this number skipped?
S-556	1971	now
S-557	1971	1974 → FAU 5221	Giant Springs Road, River Drive to Giant Springs, Great Falls
S-558	1972	1974 → FAU 5204	Smelter Avenue and River Road, 10th Street to 15th Street, Great Falls
S-559	1973	now
S-560	never?	never?	was this number skipped?
S-561	never?	never?	was this number skipped?
S-562	never?	never?	was this number skipped?
S-563	1975	2001	northwest from Springdale not in 2001 log, but on maps through 2002
S-564	1975	now
S-565	1975	now
S-566	1975	now
S-567	1994 ← 508 (part)	now
S-568	1976	now
S-569	2001	now	had been 274 until 1985-1987
S-569	1976	1981	Johnson Lane, east of Billings
S-570	2001?	2012?	first appears in the 2001 log, which claims it was created in 1993; first map is 2002; became part of S-412 when the bridge opened?
S-571	2001	now	had been 362 until 1975-1976
S-572	2001	now	had been 542 until 1975-1976
S-573	2001	now	had been 515 until 1975-1976
S-574	2006	now	creation date from 2011 log (p. 237)
MT 789	1954	1971	completely overlapped other routes