Fort Crawford was an outpost of the United States Army located in Prairie du Chien, Wisconsin, during the 19th century. The army's occupation of Prairie du Chien spanned the existence of two fortifications, both of them named Fort Crawford. The first of was occupied from 1816 to 1832, the second from 1832 to 1856. Both of the forts formed part of a string of …Fort Crawford was an outpost of the United States Army located in Prairie du Chien, Wisconsin, during the 19th century. The army's occupation of Prairie du Chien spanned the existence of two fortifications, both of them named Fort Crawford. The first of was occupied from 1816 to 1832, the second from 1832 to 1856. Both of the forts formed part of a string of fortifications along the upper Mississippi River that also included Fort Snelling near Saint Anthony Falls in Minnesota, and Fort Armstrong in Rock Island, Illinois. Fort Crawford was also associated with a string of forts built along the Fox-Wisconsin Waterway, which included Fort Winnebago in Portage, Wisconsin and Fort Howard in Green Bay, Wisconsin.