About 500 million years ago, a shallow sea covered the area, laying down layers of sand and minerals that make up much of the sandstone bluffs now seen along the river.

citation

Wikipedia contributors. (2023, November 7). St. Croix River (Wisconsin–Minnesota). In Wikipedia, The Free Encyclopedia. Retrieved February 6, 2024, from https://en.wikipedia.org/w/index.php?title=St._Croix_River_(Wisconsin%E2%80%93Minnesota)&oldid=1183996131

Houlton, Wisconsin (Wikipedia) Houlton is an unincorporated census-designated place located in St. Croix County, Wisconsin, United States. Houlton is located across the St. Croix River from Stillwater, Minnesota, in the town of St. Joseph. Houlton has no post office but has been assigned the ZIP code 54082. As of the 2010 census, its population was 386.

St. Croix River (Wisconsin–Minnesota) (Wikipedia) The St. Croix River (/ˈkrɔɪ/ KROY; French for ‘Holy Cross’), also known in Dakota as Hoġan Wanḳe Kin, is a tributary of the Mississippi River, about 169 mi (272 km) long, in the U.S. states of Wisconsin and Minnesota. The lower 125 mi (201 km) of the river form the border between Wisconsin and Minnesota. The river is a National Scenic Riverway under the protection of the National Park Service. A hydroelectric plant at the Saint Croix Falls Dam supplies power to the Minneapolis–Saint Paul metropolitan area.