Crosby is a city in Crow Wing County, Minnesota, United States. It is part of the Brainerd Micropolitan Statistical Area. Crosby is adjacent to its twin city of Ironton. It is one of the cities in the Cuyuna Range. Crosby was the location of the worst mining disaster in Minnesota, the Milford Mine disaster. On February 5, 1924, a new tunnel was blasted too close to nearby Foley Lake, and water rushed in, killing 41 miners.