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Database Decoder Routes Guide Map History FAQ

SD

Interstates in South Dakota

2 Interstate routes run through South Dakota: 2 primary.

29 Primary / North-south I-29

Kansas City to the Canadian border

Active 90 Primary / East-west I-90

Seattle to Boston

A reference atlas for the U.S. Interstate Highway System: active routes, the numbering logic, and every possible designation.

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Reference data only. Verify against FHWA, AASHTO, and state DOT records. See sources and method. Built as a static site. About the data