Cottage Grove is a city 10 miles (16 km) south of Saint Paul in Washington County in the State of Minnesota. It lies on the north bank of the Mississippi River, north of the confluence with the St. Croix River. Cottage Grove and nearby suburbs form the southeast portion of Minneapolis-Saint Paul, the 16th-largest metropolitan area in the United States, with about 3.69 million residents. Its population was 38,839 at the 2020 census.

Washington County is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 267,568, making it the fifth-most populous county in Minnesota. Its county seat is Stillwater. The largest city in the county is Woodbury, the eighth-largest city in Minnesota and the fourth-largest Twin Cities suburb.