Flint is a city in the U.S. state of Michigan and is located along the Flint River, 66 miles 106 square kilometers northwest of Detroit. It is the county seat of Genesee County which lies in the Flint Tri-Cities region of Michigan. Flint is the county seat of Genesee County in the Flint/Tri-Cities region of Michigan. Genesee County largely comprises the entirety of Flint's metropolitan area, the fourth largest metropolitan area in Michigan with a population of 425,790 in 2010. Flint is best known as the birthplace of General Motors (GM), and also the Flint Sit-Down Strike of 1936–37 that played a vital role in the formation of the United Auto Workers. Flint is also home to the headquarters of Citizens Republic Bancorp. Bishop International Airport is also considered to be part of the city, even though it is surrounded by Flint Township and Mundy Township.