In summertime, target rainbow trout in deeper, cooler waters near the dam and channels with bait. Bass and other warmwater fish are active in shallow coves during early mornings and evenings. Hagg Lake is one of western Oregon's largest lakes and is a premier warmwater fishing destination. The lake is home to both the state record smallmouth bass and bullhead catfish.

Current reservoir level can be found here. Maintained and operated by Washington County, the park features numerous picnic areas, two boat launching facilities, more than 15 miles of hiking trails, and observation decks for wildlife and bird watching. The lake and lake park are currently open, although users are encouraged to check the Hagg Lake Park website, as conditions can change.