Wisconsin Highway 51
{{Short description|Former state highways in Wisconsin, United States}}
{{Use mdy dates|date=January 2025}}
{{Infobox road
|state=WI
|type=WI 1919
|route=51
|established=1918
|deleted=1926
|previous_type=US
|previous_route=51
|next_type=WI
|next_route=52
}}
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:
- Highway 51 from 1917 to 1923, along the current route of U.S. Highway 63 from Turtle Lake to Spooner.
- Highway 51 from 1923 to 1936, currently routed as Highway 72 from Ellsworth to Downsville.
- For the highway in Wisconsin numbered 51 since 1926, see U.S. Highway 51.