Spruce Run Recreation Area in rolling Hunterdon County is popular for picnicking, camping, boating and fishing. Spruce Run Reservoir was one of the first water supply facilities built and operated by the state, with 1,290 acres of water and 15 miles of shoreline, the third largest reservoir in New Jersey after Round Valley and Wanaque. The gate is open daily from 8 a.m. to 6 p.m.