Wisconsin Highway X151

Wisconsin Highway X151 (WIS X151) is a proposed state highway in the state of Wisconsin that would run within the city limits of Madison for its entirety.

Currently, U.S. Highway 151 (US 151) runs through the city of Madison on Park Street, West Washington Avenue, Proudfit Street, North Shore Drive, John Nolen Drive, Blair Street, and East Washington Avenue. The city had talked about upgrades to Park Street for years, but following the tragic death of a 17-year old on Park Street in February of 2026, there has been an enormous spike in discussion about upgrading it.

The Wisconsin Department of Transportation has proposed rerouting US 151 onto US 12/18 and I-39/I-90 in the Madison area, and if implemented, the "Connecting Highway" designation would be removed between the Park Street/US 14 east interchange and the I-39/90/94 & US 151 interchange.