Ossipee Lake is located in Carroll County in eastern New Hampshire, in the communities of Ossipee and Freedom. At 3,257 acres, it is the sixth-largest lake located entirely in New Hampshire. The lake is fed by the West Branch, the Bearcamp and Lovell rivers, and the Pine River. Water leaves the eastern end of the lake via the Ossipee River, flowing to th…Ossipee Lake is located in Carroll County in eastern New Hampshire, in the communities of Ossipee and Freedom. At 3,257 acres, it is the sixth-largest lake located entirely in New Hampshire. The lake is fed by the West Branch, the Bearcamp and Lovell rivers, and the Pine River. Water leaves the eastern end of the lake via the Ossipee River, flowing to the Saco River in Maine.