Bufallo Rock State Park & Effigy Tumuli is a state park and historical education area located in Ottawa, Illinois. It is considered part of the Illinois State Park system and is managed by the Illinois Department of Natural Resources.

Buffalo Rock State Park is located on a bluff in the Illinois River. In the past the area was an island in the river itself and as such it offers amazing views of the Illinois river and the surrounding area. The island itself was settled by the Illinois Indians. Unfortunately the Illinois tribe was virtually wiped out by a protracted war conducted against the Iroquois.

Effigy Tumuli is a memorial tribute to the native American burial grounds in the area. The installation depicts five sculptures native to the Illinois River area.