Mammoth Springs State Park in northern Arkansas by the Missouri border is the largest spring in Arkansas, and a great spot to take a short break on the scenic route between Little Rock and St. Louis. There isn't a lot to see or do at the state park once you take a short walk around the spring, but there is a small railroad depot museum with a caboose, and a few picnic areas.
The surrounding area on the Spring river has a lot more to do, with canoe rentals, campgrounds, outfitting, and vacation rentals being a decent part of the local economy.
