Hillsborough County, New Hampshire

Hillsborough County
County
Manchester skyline
Seal
Location within the U.S. state of New Hampshire
New Hampshire's location within the U.S.
Coordinates: 42°53′44″N 71°34′58″W / 42.895584°N 71.582741°W / 42.895584; -71.582741
Country	United States
State	New Hampshire
Founded	1769
Named for	The Earl of Hillsborough
Seat	Manchester and Nashua
Largest city	Manchester (by population) Weare (by area)
Area
• Total	892.5 sq mi (2,312 km2)
• Land	876.5 sq mi (2,270 km2)
• Water	15.9 sq mi (41 km2)  1.8%
Population  (2020)
• Total	422,937
• Estimate  (2022)	426,594
• Density	486.7/sq mi (187.9/km2)
Time zone	UTC−5 (Eastern)
• Summer (DST)	UTC−4 (EDT)
Congressional districts	1st, 2nd
Website	hcnh.org

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,^[1] 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.

Hillsborough County comprises the Manchester-Nashua, NH Metropolitan Statistical Area, which in turn constitutes a portion of the Boston-Worcester-Providence, MA-RI-NH-CT Combined Statistical Area.