Coldwater is a city in the U.S. state of Michigan. As of the 2010 census, the city population was 10,945. It is the county seat of Branch County, located in the center of the southern border of Michigan.Coldwater is at 41°56′25″N 85°00′02″W / 41.94028°N 85.00056°W / 41.94028; -85.00056. The ZIP code is 49036 and the FIPS place code is 17020. The elevation is 969 feet above sea level. The City of Coldwater is entirely surrounded by the Township of Coldwater.