List of lettered highways in Maine

Lettered highways in Maine
Maine's early highway system
System information
Maintained by MaineDOT
Highway names
Interstates	Interstate x (abbreviated I-X)
US Highways	U.S. Route x (abbreviated US-X)
State	State Route x or Route x (abbreviated SR X)
Lettered routes	Route x
System links
Maine State Highway System Interstate US State Auto trails Lettered highways

Beginning in 1914, Maine used a system of lettered highways to internally designate cross-state routes. Surveys were carried out in 1913 to determine which roads would be slated for upgrade, and ultimately three hundred and seventy miles were designated for upgrade. The following year, Maine designated 21 trunk highways to be maintained by the state, lettered A through T and X. By the time of the system's designation, three routes, lettered U, V, and W, had been surveyed, but not approved by the State Highway Commission, though plans were in place to include these routes at a later date. These routes were only ever intended to be internal designations; there are no provisions provided in the financial records of the Commission indicating signage was expended on at this time. This internal designation was supplemented by systems for public use; pole-marked auto trails were introduced by the State Highway Commission in 1919, which were replaced in 1925 by the implementation of the New England interstate highway system, which in turn were replaced by a renumbering in 1933. Through these changes, the lettered designations remained for internal purposes, with expansions including spurs and suffixed routes. In 1955, the commission finally abandoned these internal designations and began referring to them by their signed designations.

List of routes

The list below refers only to designations established in 1914; later additions included suffixed routes and more spurs.

Route	From	Through	To	Modern designation	Notes
A	Kittery	York, Wells, Kennebunk, Biddeford, Saco, Scarboro, South Portland	Portland	US 1
A Spur	Berwick	North Berwick	Wells	SR 9	Begun in 1923
		Kennebunk			Begun in 1927
	Saco		Old Orchard	SR 98	Begun in 1935
A-2	Wells		Sanford	SR 109
A-5		Berwick
B	Fryeburg	Bridgton, Naples, Casco, Raymond, Windham, Westbrook	Portland	US 302
B–S	Naples	Casco	Poland	SR 11
B–S-2		Norway		SR 117
C	Portland	Falmouth, Cumberland, Yarmouth, Freeport, Brunswick, West Bath	Bath	US 1 (including Old Bath / Brunswick Road)
C-1	Brunswick	West Bath	Bath	US 1
D	Woolwich	Wiscasset, Edgecomb, Alna, Newcastle, Damariscotta, Nobleboro, Waldoboro, Warren, Thomaston, Rockland, Rockport, Camden, Lincolnville, Northport	Belfast	US 1
D Spur	Thomaston	South Thomaston	St. George	SR 131	Begun in 1917
	Edgecomb		Boothbay		Begun in 1927
D–4	St. George		South Thomaston	SR 131	Begun in 1937
E	Portland	Falmouth, Cumberland, Gray, New Gloucester, Auburn, Lewiston, Greene, Monmouth, Winthrop, Manchester	Augusta	SR 100, US 202
F	Auburn	Turner, Livermore, East Livermore, Jay, Wilton, Farmington, Strong, Avon, Phillips, Sandy River Plantation	Rangely	SR 4
F–O	Dixfield	Carthage	Wilton	US 2	Begun in 1928
G	Augusta	Sidney, Belgrade, Oakland	Waterville	SR 27, SR 11
H	Augusta	Vassalboro, Winslow, Waterville, Fairfield, Skowhegan, Norridgewock, Madison, Anson, Embden, Solon, Bingham, Moscow, Caratunk Plantation, The Forks Plantation, West Forks Plantation, Johnson Mountain, Parlin Pond, Jackman Plantation, Moose River Plantation, Dennistown Plantation, Sandy Bay Plantation	Quebec Line	US 201, US 201A, US 201
H–I	Skowhegan	Canaan, Pittsfield, Palmyra	Newport	US 2	Begun in 1928
H–3	Skowhegan	Madison	Solon	US 201	Begun in 1928
I	Fairfield	Benton, Clinton, Burnham, Pittsfield, Palmyra, Newport, Etna, Carmel, Herman	Bangor	SR 100, US 2
J	Newport	Corinna, Dexter, Dover, Foxcroft, Guilford, Abbot, Monson, Shirley	Greenville	SR 7, SR 23, SR 6
J–K	Enfield	Howland, LaGrange, Orneville, Milo, Sebec, Dover, Foxcroft	Guilford	SR 155, SR 6	First attested to in 1924. Alignments in Medford and Maxfield are also attested
K	Bangor	Veazie, Orono, Oldtown, Milford, Greenbush, Passadumkeag, Enfield, Lincoln, Winn, Mattawamkeag, Molunkus, Medway, Stacyville, Sherman, Crystal, Island Falls, Dyer Brook, Merrill, Smyrna, Ludlow, New Limerick, Houlton, Littleton, Monticello, Bridgewater, Blaine, Mars Hill, Easton, Presque Isle, Caribou, Connor, Cyr, Van Buren, Grand Isle, Madawaska, Frenchville	Fort Kent	US 2, US 1	1916: realigned between Stillwater and Enfield to follow Stillwater Avenue over the Stillwater bridge, then modern-day SR 16 to LaGrange and SR 155 to Enfield; however, this alignment wasn't kept, and was partially absorbed by Route J–K
K Spur	Easton	Fort Fairfield	Canada line	US 1A, SR 161	First attested to in 1924
	Houlton		Canada line	US 2
K–1	Presque Isle	Westfield	Mars Hill	US 1	First attested to in 1928
K–2	Fort Fairfield	Limestone, Caswell	Hamlin	US 1A	First attested to in 1931
K–6		Fort Fairfield
K–7		Houlton
K–8	Glenwood	Haynesville	Houlton	US 2A
L	Belfast	Searsport, Stockton Springs, Prospect, Frankfort, Winterport, Hampden	Bangor	US 1, US 1A
L Spur		Prospect	Waldo-Hancock Bridge	SR 174	First attested to in 1930
L–Y	Stockton Springs	Prospect, Waldo-Hancock Bridge, Verona	Bucksport	US 1	First attested to in 1931
M	Bangor	Brewer, Holden, Dedham, Ellsworth	Trenton	US 1A, SR 3
M Spur		Bar Harbour
N	Ellsworth	Hancock, Franklin, Sullivan, Gouldsboro, Steuben, Milbridge, Cherryfield, Harrington, Columbia, Columbia Falls, Jonesboro, Whitneyville, Machias, East Machias, Whiting, Trescott, Edmunds, Dennysville, Pembroke, Perry, Robbinstown	Calais	US 1
N Spur	Perry		Eastport	SR 190
	Whiting	Trescott	Lubec	SR 189
	Columbia Falls	Addison	Jonesport	SR 187
	Ellsworth		Lamoine	SR 184
		Calais			Called Bridge Street
O	Livermore	Canton, Peru, Dixfield, Mexico, Rumford, Hanover, Newry, Bethel, Gilead	New Hampshire state line	SR 108, Main Street, US 2
O Spur	Rumford		Peru	SR 108	First attested to in 1934. Referred to as Highway O-1 in 1938.
P	Augusta	Chelsea, Whitefield, Windsor, Jefferson, Somerville, Washington, Union, Hope, Rockport	Rockland	SR 17
Q	Augusta	Hallowell, Farmingdale, Gardiner, Richmond, Bowdoinham, Topsham	Brunswick	US 201 (including SR 138)
Q Spur		Richmond			Begun in 1924
Q-1	Bowdoin	Bowdoinham	Richmond	US 201
R	Augusta	Vassalboro, China, Palermo, Liberty, Montville, Searsmont, Morrill, Waldo	Belfast	US 202, SR 3
S	Gray	New Gloucester, Poland, Mechanic Falls, Oxford, Norway, Paris, Woodstock, Greenwood	Bethel	SR 26
T	Newry	Grafton, Upton	New Hampshire state line	SR 26
U	Biddeford	Kennebunkport, Lyman, Alfred, Sanford, Lebanon	New Hampshire state line	SR 111, US 202	Not finalized by 1914 report
V	Norridgewock	Mercer, New Sharon	Farmington	US 2	Not finalized by 1914 report
W	Belgrade Depot	Rome	New Sharon	SR 27	Not finalized by 1914 report
X	Bangor	Glenburn, Kenduskeag, Corinth, Charleston, Garland, Hermon	Dover	ME 15	1916: extended over modern-day SR 6 to LaGrange
Y	Belgrade Depot	Brewer, Holden, Bucksport, Orland, Penobscot, Bluehill, Surry	Ellsworth	SR 15, SR 172	Added in 1915
Y Spur	Orland	Penobscot	Castine	SR 166	First attested to in 1926
Z	Lewiston	Lisbon	Topsham	SR 196	Added in 1917
Sokokis Trail	Cornish	Limerick, Waterboro, Lyman, Hollis, Dayton, Biddeford, Saco	Old Orchard	SR 5	First attested to in 1926
Ossipee Trail	Gorham	Standish, Limington, Cornish, Parsonfield, Porter	New Hampshire line	SR 25	First attested to in 1927
Pequaket Trail	Standish	Baldwin, Hiram, Brownfield	Fryeburg	SR 113