Michigan's 8th Congressional District Republican Committee is composed of Bay County, Genesee County, Midland County and Saginaw County.

Bay County is made up of 14 townships and 4 cities and is home to around 102,680 people, making it the 19^th most populated county in the State of Michigan and includes the cities / townships of Auburn, Bangor, Bay City, Essexville, Kawkawlin, Monitor, and Pinconning.

Genesee County is made up of 17 townships and 11 cities. Genesee County is home to an estimated 400,340 people, making it the 4^th most populated county in the State of Michigan and includes the cities / townships of Burton, Clio, Davison, Fenton, Flint, Flushing, Goodrich, Grand Blanc, Linden, Montrose, Mount Morris, Mundy, Swartz Creek, Thetford and Vienna.

Midland County is made up of 2 cities, 16 townships and 1 village. It is home to about 83,450 people, making it the 23^rd most populated county in the State of Michigan and includes the cities / townships of Coleman, Homer, Ingersoll, Jerome, Larkin, Lee, Lincoln, Midland, Mt. Haley, Porter, and Sanford.

Saginaw County contains 3 cities, 27 townships and 5 incorporated villages and is home to approximately 190,120 people, making it the 10^th most populated county in Michigan and includes the cities / townships of Birch Run, Bridgeport, Buena Vista, Chesaning, Frankenmuth, Freeland, Saginaw, St. Charles, Thomas Twp, and Zilwaukee.