Crow Creek, 140 mi/225 km long, SE Wyo. and NE Colo.; rises in Laramie Mts., SW Laramie co., Wyo.; flows E past Cheyenne, then S into Colo., passes between units of Pawnee Natl. Grassland, joins South Platte R. in Weld co., 13 mi/21 km E of Greeley, Colo.