Michigan's 31st Senate district is one of 38 districts in the Michigan Senate.

The 31st district was created by the 1850 Michigan Constitution, as the 1835 constitution only permitted a maximum of eight senate districts.

[2][3] It has been represented by Republican Roger Victory since 2023, succeeding fellow Republican Kevin Daley.

District 31 encompasses parts of Allegan and Ottawa counties.

[4] District 31, as dictated by the 2011 Apportionment Plan, covered all of Bay, Lapeer, and Tuscola Counties along Saginaw Bay, including the communities of Bay City, Essexville, Caro, Vassar, Lapeer, Imlay City, Almont, Bangor Township, Monitor Township, and Hampton Township.