The Unofficial South Dakota
Highways Page

Welcome to the South Dakota Highways page! Settle in, and we'll take a ride across the Rushmore State.

Interstate Highways

Two multi-state Interstate Highways pass through South Dakota. I-90 is the west-east interstate, and runs across the southern part of the state. I-29 runs north-south across the eastern portion of the state. Each has its own spur going around or through a city (I-190 in Rapid City, and I-229 in Sioux Falls). Interstate construction was completed in 1983, with I-29 in the northeast part of the state. South Dakota makes use of the "Business" Interstate routes as well.

US Highways

Several U.S. highways pass through South Dakota as well. The east-west routes are US-12, US-212, US-14, US-16, historic US-216, and US-18 (in order from north to south). The north-south routes are US-385 (former US-85E), US-85, US-83, US-183, US-281, US-81, and the former US-77 (in order from west to east).

State Highways

Many of South Dakota's current state highways received their designations in the mid 1920's, with the general format of numbering staying the same. East-west roads have even numbers, and north-south roads have odd numbers. Numbers increase from north to south, and from east to west. However, most of the 3-digit state numbers do not follow this convention (although the even/odd numbering does apply). There appears to have been only a couple instances of a 1-digit state highway (SD-8 in northwest and north central South Dakota, now a part of SD-20, and SD-9 in northeast South Dakota, currently unnumbered).

Bureau of Indian Affairs Highways

The Bureau of Indian Affairs (BIA) has highway systems in the Indian Reservations of western South Dakota. Official state highway maps indicate the numbers for these roads (Rand McNally atlases show the roads, but not the numbers).

Other Highways

Many of South Dakota's counties maintain a network of numbered county roads. In the Black Hills, the U.S. Forest Service also has a network of numbered roads. Neither of these will be covered on these pages.

My sources of South Dakota highway information:

• 1932 Standard Oil map of South Dakota.
• 1936 Conoco Oil map of South Dakota.
• 1936 U.S. highway map from the National Map Company.
• Skelly Oil map of South Dakota from 1938.
• Skelly Oil map of North and South Dakota from 1939.
• Early 1950's DX Map of North and South Dakota, published by H.M. Gousha Corp.
• Hammond's World Atlas, Volume 2 (U.S. maps) from 1969.
• 1971 Standard Map of North and South Dakota, published by Diversified Map Corp.
• Rand McNally road atlases from 1926, 1940, 1950, 1954, 1960, 1964, 1975, 1980, and 1987 through 2003.
• National Geographic road atlas from 1998 through 2001.
• State highway maps from 1941, 1944, 1948, 1953, 1957, 1962, 1963, 1965, 1971, 1977, 1981, 1984, 1989, 1999, and 2002.
• South Dakota Atlas and Gazetteer from 1997 and 2001.
• 1998 5-year construction plan, put out by the South Dakota Department of Transportation.
• South Dakota state laws regarding highway alignments.

I'd appreciate any other information that you may have; feel free to E-mail me at chris-g@dm.net.

The following pages are the most current listings of Interstate, U.S., state, and BIA highways that I have. These include historical highways (no longer exist, or have been significantly relocated from the original alignment) and details on each particular road.

Highways 1 through 30

Highways 31 through 60

Highways 61 through 100

Highways 101 through 199

Highways 200 and above

Signs and Sights of South Dakota

Photos and Trip Reports

Exit listings for:

• I-29
• I-90
• I-190
• I-229

Or, cruise the highways of North Dakota and Nebraska, two other states which I have covered.

South Dakota Road Conditions (provided by the South Dakota Dept. of Transportation.

Standard Disclaimer: This site is not affiliated in any way, shape, or form with the South Dakota Department of Transportation.