Green Bay is a city in and the county seat of Brown County in the U.S. state of Wisconsin, at the head of Green Bay, a sub-basin of Lake Michigan, at the mouth of the Fox River. It is 581 feet above sea level and 112 miles north of Milwaukee. The population was 104,057 at the 2010 census. Green Bay is the third-largest city in the state of Wisconsin, after Milwaukee and Madison, and the third-largest city on Lake Michigan's west shore, after Chicago and Milwaukee.