This day-use park east of Umatilla
, lies on the south shore of Lake Wallula and contains the interesting geological formation from which it gets its name. Hat Rock was the first distinctive landmark passed by Lewis and Clark on their journey down the Columbia River.
The park is popular with fishermen, waterskiers, jetskiers, and boaters. There is a pond, stocked with rainbow trout, a sand volleyball court, and four reservable picnic areas.