The main village of the town, where 2,156 people resided at the 2020 census,[4] is defined as the Hillsborough census-designated place (CDP), and is located along the Contoocook River at the junction of New Hampshire Route 149 with Henniker Street and Main Street.

The town was first granted in 1735 by Jonathan Belcher, colonial governor of Massachusetts and New Hampshire, as "Number Seven", one in a line of nine Massachusetts towns set up as defense barriers against Indian attacks.

A cluster of five stone arch bridges built during the 19th century in Hillsborough is designated as a National Historic Civil Engineering Landmark.

Rail service north to Henniker ceased in 1942, and Hillsborough became the end point on a line that once stretched in an arc from Nashua to Concord, New Hampshire.

Hillsborough was once home to an iconic railroad covered bridge and a curved wooden trestle.

[2] The town center, or census-designated place, has a total area of 1.9 square miles (5.0 km2).

[6] The highest point in Hillsborough is Thompson Hill, at 1,768 feet (539 m) above sea level, in the northern part of town.

Hillsborough is drained by the Contoocook River and its tributaries, Beards and Sand brooks.