Prior to the primary highway system which exists in the U.S. state of Iowa today, signed highway routes known as auto trails were registered with the Iowa State Highway Commission. Organizations, such as the Lincoln Highway Association, volunteered to sponsor and register certain roads with the highway commission. Each organization chose their colors and designed route markers to guide motorists along the way. Eventually, confusion reigned and the highway commission took action. Beginning in 1920, primary road numbers were assigned to registered routes. Some of these registered routes, most notably the Lincoln Highway, are still famous today, while most have been long forgotten.

	Atlantic–Yellowstone–Pacific Highway      National route. Analogous to Iowa Highway 9, U.S. Route 71, U.S. Route 18, U.S. Route 218, and U.S. Route 20
	Black Diamond Trail    Marshalltown to Cedar Falls  Roughly analogous to Iowa Highway 14 and U.S. Route 20
	Black Hawk Trail    Davenport to Davenport
	Black Hills Highway      National Route. Analogous to U.S. Route 18
	Blue Grass Route    Council Bluffs to Burlington Counties: Adams 'Analogous to U.S. Route 34
	Blue J Highway    Lineville to Des Moines  Roughly analogous to U.S. Route 65 and Iowa Highway 14
	Burlington Way    Burlington to Cresco  Roughly analogous to U.S. Route 61, Iowa Highway 70, U.S. Route 218, Iowa Highway 150, and U.S. Route 63
	Capitol Highway    Lineville to Des Moines  Analogous to U.S. Route 69
	Cedar Rapids, Ottumwa, and McGregor Trail    Ottumwa to McGregor  Also known as the Park Highway. Analogous to Iowa Highway 149 and U.S. Route 151
	Cedar Rapids, Urbana–Independence Short Line    Cedar Rapids to Independence  Roughly analogous to Iowa Highway 150
	Center Point Motor Club    Cedar Rapids to St. Paul, Minn.  Roughly analogous to Iowa Highway 150 and U.S. Route 63
	Chariton and Leon Short Line    Leon to Chariton  Analogous to U.S. Route 69 and U.S. Route 34
	Custer Battlefield Highway    Omaha, Nebr. to Glacier National Park  Analogous to Interstate 29 and Iowa Highway 12
	Daniel Boone Trail    St. Louis, Mo. to St. Paul, Minn. Counties: Boone Analogous to U.S. Route 63, Iowa Highway 163, Iowa Highway 415, Iowa Highway 17, U.S. Route 30, and U.S. Route 169
	Denison – Sioux City Cut-Off    Denison to Sioux City
	Detroit, Lincoln, and Denver Highway    Denver, Colo. to Detroit, Mich.
	Diagonal Trail    Davenport to Lake Park
	Diamond Trail    Des Moines to Iowa City Counties: Benton
	Eldora – State Center and Colfax Highway    Colfax to Eldora
	Everett Powers Highway    Des Moines to Knoxville
	Farmers Highway    Exira to Greenfield
	Glacier Trail    St. Louis, Mo. to Glacier National Park
	Golden Rod Highway    Nebraska City, Nebr. to Bedford
	Grand Line    Lamoni to Hopeville
	Great White Way    Council Bluffs to Davenport Counties: Adair Current routes: U.S. Route 6
	Green Crescent    Muscatine to Cedar Rapids
	Hamlin Short Route    Elk Horn to Guthrie Center
	Harding Highway    Los Angeles, Calif. to Washington, D.C.
	Hawkeye Cut-Off    Sioux City to Fort Dodge
	Hawkeye Highway    Sioux City to Dubuque Counties: Black Hawk Current routes: U.S. Route 20, U.S. Route 218
	Herbert Hoover Highway    Iowa City to Lowden
	Imperial Highway    Sioux Falls, S. Dak. to Lansing
	Indian Trail    Tama to Eldora
	I.O.A. Short Line    Council Bluffs to Davenport
	Jefferson Highway    New Orleans, La. to Winnipeg, Man.
	John D. Parmalee Trail    Des Moines to Pleasantville
	King's Highway    Cedar Rapids to Davenport
	Lincoln Hawkeye Pike    Clinton to West Union
	Lincoln Highway    San Francisco, Calif. to New York, N.Y.
	Lineville–Indianola Short Line    Lineville to Indianola
	Marshalltown–Colfax Short Line    Colfax to Marshalltown
	Marysville–Carroll Trail (M.C. Trail)    Maryville, Mo. to Carroll
	Mississippi Valley Highway    Louisiana to Minnesota  Followed the same route as the Burlington Way.
	Muscatine – Des Moines Short Line    Des Moines to Muscatine
	National Parks Pike    Yellowstone National Park to Madison, Wis.
	Okoboji Trail    Des Moines to Arnolds Park
	Old Military Trail    Charles City to McGregor
	Perry Pike    Guthrie Center to Ogden
	Pershing Way    New Orleans, La. to Winnipeg, Man.
	Rainbow Trail    Hawarden to Dubuque
	Red Ball Route    St. Louis, Mo. to St. Paul, Minn.
	Red Line Route    Missouri state line to Villisca
	Red X Route — 87 miles (140 km)  Iowa City to Dubuque  Current routes: Iowa Highway 1 and U.S. Route 151 Passed through Iowa City, Mount Vernon, Anamosa, Monticello, and Dubuque
	River to River Route    Council Bluffs to Davenport Counties: Audubon
	Southwest Trails    Kansas City, Mo. to Chicago, Ill. Counties: Appanoose Current routes: Iowa Highway 5
	Star Route    Osceola to Des Moines
	Tall Corn Route    Sioux City to McGregor
	Tourists Route    Mount Ayr to Des Moines
	Washington Highway    Seattle, Wash. to Washington, D.C.
	Waubonsie Trail    Nebraska City, Nebr. to Keokuk
	Webster Trail    Keokuk to Mt. Pleasant
	Whiteway–7–Highway    Omaha, Nebr. to Chicago, Ill.
	Wilson Highway    Missouri state line to Emmons, Minn.
	Woodward–Ogden Cut-Off    Des Moines to Ogden