List of auto trails in Maine


Maine was one of the first states to mark their state highway system. From 1914 to 1925, Maine used a system of lettered highways to designate cross-state routes. This system was the first of its kind in the United States coordinated by a single state, predating Wisconsin's system by three years. In 1919, this system was supplanted by a series of auto trails officially created by the State Highway Commission, though it is unclear as to whether this system completely supplanted the lettering system. Both systems were abandoned by 1925 in favor of the New England interstate highway system.

List

In 1919, the Maine Automobile Association and the Maine State Highway Commission collaborated to create a series of state-designated auto trails. The system posed a stark contrast to the auto trail systems of other states, which were often private endeavors, with improvements by these booster organizations ranging from simple marked poles to paving and maintenance of the road. It is unclear which routes listed below existed at what times.
RouteColorsFromThroughToLettered routeReplacement Modern designationNotes
Atlantic HighwayBlueNew Hampshire LineKittery, Wells, Kennebunk, Scarborough, Portland, Yarmouth, Brunswick, Bath, Wiscasset, Waldoboro, Rockland, Belfast, Searsport, Bangor, Ellsworth, Hancock, Millbridge, Jonesboro, Machias, Dennysville, Perry, RobbinstonCalaisA, C, D, L, M, NRoute 1US 1
Longfellow HighwayYellowNew Hampshire LineBethel, Bryant Pond, West Paris, South Paris, Norway, Poland, GrayPortlandO, SRoute 15US 2, SR 26
Theodore Roosevelt International HighwayWhite
Red
White		New Hampshire LineFryeburg, Bridgton, Naples, Raymond, North Windham, Highland LakePortlandBRoute 18U.S. 302
Grafton Notch HighwayWhite
Yellow		New Hampshire LineUpton, NewryBethelT, ORoute 26US 2
International TrailRedBrunswickGardiner, Augusta, Waterville, Skowhegan, Norridgewock, Anson, Solon, Caratunk Plt, Jackman StationCanada LineQ, HRoute 20U.S. 201, U.S. 201A
Aroostock TrailWhite
Blue		FairfieldClinton, Pittsfield, Newport, Bangor, Old TownLincolnI, KRoute 100, 15, US 2, 1923: Extended to Houlton, then Mars Hill, Presque Isle, Caribou, Van Buren, Madawaska to Canada Line
Capital WayBlue
White		PortlandLewistonAugustaERoute 100SR 100, US 202
Kennebec-Penobscot TrailOrange
White		AugustaSouth China, Liberty, Searsmont, BelmontBelfastRRoute 102US 202, SR 3
Mount Desert TrailYellow
White		EllsworthHulls CoveBar HarborMRoute 183SR 183, SR 3
Brunswick-Greenville HighwayGreen
White		NewportDexter, Dover, Guilford, Abbott, MonsonGreenvilleJRoute 104SR 7, SR 23, SR 6
Poland Springs-White Mountain TrailGreenNaplesCasco, PolandMechanic's FallsRoute 116SR 111