State Trunk Highway 51 (often called Highway 51, STH-51 or WIS 51) was a number assigned to two different state highways in the U.S. state of Wisconsin:

State Trunk Highway 51 marker
State Trunk Highway 51
Route information
Maintained by WisDOT
Existed1918–1926
Location
CountryUnited States
StateWisconsin
Highway system
US 51 WIS 52