Lake Arthur Estates is a census-designated place and mobile home court located in Muddy Creek Township, Butler County, in the U.S. state of Pennsylvania. Located near the intersections of I-79 and US 422, the village is situated west of Lake Arthur, a reservoir on Muddy Creek. The community is also just west of Moraine State Park, which surrounds the lake. As of the 2010 census the population was 594.