Lancaster is a town in Coos County, New Hampshire, USA, on the Connecticut River named after Lancaster, England. It is the county seat of Coos County and gateway to the Great North Woods Region. Lancaster, which includes the villages of Grange and South Lancaster, is home to Weeks State Park and the Lancaster Fair. Part of the White Mountain National Forest is in the eastern portion. The town is part of the Berlin, NHVT Micropolitan Statistical Area. Many water-powered mills have come and gone, including sawmills, several potato starch mills, one of the largest gristmills in the state, and carriage factories. A granite quarry operated in the Kilkenny Range. With fertile meadows beside the Connecticut River, Lancaster was in 1874 the twelfth most productive agricultural town in the state. An extension of the Boston, Concord & Montreal Railroad shipped products to market, and brought tourists to the grand hotels in the area.