Lancaster is a town located along the Connecticut River in Coös County, New Hampshire, United States.

It was the first settlement north of Haverhill, New Hampshire, 50 miles (80 km) to the south, and originally included land in what is now Vermont.

Reverend Joshua Weeks, a grantee of the town, was among the group of explorers who named the mountains of the Presidential Range.

Other grantees were Timothy Nash and Benjamin Sawyer, who discovered Crawford Notch in 1771, making a shorter route to Portland, Maine, possible.

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.

Just south of the village center is Mount Prospect, summer home to Senator John W. Weeks, who sponsored congressional legislation creating White Mountain National Forest.

Lancaster's highest point is located on a western spur of Mount Cabot at 3,290 feet (1,000 m) above sea level.

Lancaster has a humid continental climate (Dfb) with warm summers coupled with cool nights, and cold, snowy winters with annual snowfall averaging 70.3 inches (179 cm).As of the census of 2010, there were 3,507 people, 1,399 households, and 880 families residing in the town.

As of January 2006, Lancaster is also served by the Tri-Town Bus, a public transportation route connecting with Whitefield and Littleton.