Lake Nockamixon is a reservoir in southeastern Pennsylvania, United States, and the largest lake in Bucks County. It is formed by a dam on Tohickon Creek and is the centerpiece of Nockamixon State Park. Swimming is not allowed in the lake, but boating is popular. The park maintains a marina and a boat rental as well as three other boat-launch areas. Fishing is also popular, and common species include striped bass, walleye, pickerel, carp, largemouth and smallmouth bass, muskellunge, and catfish. The water is stained by vegetation and has a very faint current, since the lake is part of the course of Tohickon Creek.