Antrim is a town in Hillsborough County, New Hampshire, United States. The population was 2,651 at the 2020 census. The main village in the town, where 1,395 people lived at the 2020 census, is defined as the Antrim census-designated place (CDP) and is located at the intersection of U.S. Route 202 and New Hampshire Route 31. The town of Antrim also includes the villages of Antrim Center, North Branch, and Clinton Village.

Hillsborough County is the most populous county in the U.S. state of New Hampshire. As of the 2020 census, the population was 422,937, almost one-third the population of the entire state. Its county seats are Manchester and Nashua, the state's two biggest cities. Hillsborough is northern New England's most populous county as well as its most densely populated.