Yellowstone Lake State Park is a Wisconsin state park. The Yellowstone Lake is a reservoir on a tributary of the Pecatonica River. The state park is included in the Yellowstone Lake State Wildlife Area.
Located near Blanchardville in Lafayette County, in the town of Fayette, the man-made lake is sustained by the Yellowstone River which enters on the northwest side, and the man-made dike built on the southeast side. The dam, at the far southern end of the dike, is crossed by a narrow, steel catwalk, from which fishing is not allowed.