Marine on St. Croix or Marine on Saint Croix is a city in Washington County, Minnesota, United States. The population was 689 at the 2010 census. It was founded in 1839 as Marine Mills. The city was the site of the first commercial sawmill on the St. Croix River. A substantial portion of the city is listed as a historic district on the National Register of Historic Places and by the state of Minnesota.

Walter Norris Kirn is an American novelist, literary critic, and essayist. He is the author of eight books, most notably Up in the Air, which was made into a film of the same name starring George Clooney.