Michigan's 13th Senate district is one of 38 districts in the Michigan Senate. The 13th district was created by the 1850 Michigan Constitution, as the 1835 constitution only permitted a maximum of eight senate districts. It has been represented by Democrat Rosemary Bayer since 2023, following her victory over Republican Jason Rhines.
District 13 encompasses parts of Oakland and Wayne counties.
District 13, as dictated by the 2011 Apportionment Plan, covered eastern Oakland County in the northern suburbs of Detroit, including Troy, Rochester Hills, Royal Oak, Berkley, Clawson, Birmingham, Bloomfield Hills, and Rochester.
The district was split among Michigan's 8th, 9th, and 11th congressional districts, and overlapped with the 26th, 27th, 40th, 41st, and 45th districts of the Michigan House of Representatives.