The Shiawassee River in the U.S. state of Michigan drains an area of 1,201 square miles (3,110 km2) within Oakland, Genesee, Livingston, Shiawassee, Midland and Saginaw counties. It flows in a generally northerly direction for approximately 110 miles (180 km) from its source to its confluence with the Tittabawassee River creating the Saginaw River, which drains into Saginaw Bay of Lake Huron.

Genesee County is a county in the U.S. state of Michigan. As of the 2020 Census, the population was 406,211, making it the fifth-most populous county in Michigan. The county seat and population center is Flint. Genesee County consists of 33 cities, townships, and villages. It is considered to be a part of the greater Mid Michigan area.