[2] The Crawfish River rises in Columbia County and initially flows eastward in a broadly meandering course, collecting the North Branch Crawfish River and passing the city of Columbus.

Aztalan State Park is along the river in Jefferson County at the site of a 10th - 13th Century Native American settlement.

Shortly before merging the Rock and Crawfish rivers cross under Interstate 94.

Both rivers flood the nearby land on an annual basis.

In 2008, some lanes on I-94 were temporarily closed due to flooding from both rivers.