Hillsborough County is the most populous county in the U.S. state of New Hampshire. As of the 2010 census, the population was 400,721. The population was estimated at 415,247 in 2018. Its county seats are Manchester and Nashua. 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.
According to the U.S. Census Bureau, the county has a total area of 892 square miles (2,310 km), of which 876 square miles (2,270 km) is land and 16 square miles (41 km) (1.8%) is water. The highest point in Hillsborough county is Pack Monadnock Mountain at 2,290 feet (700 m).
As of the 2010 United States Census, there were 400,721 people, 155,466 households, and 103,959 families residing in the county. The population density was 457.4 inhabitants per square mile (176.6/km). There were 166,053 housing units at an average density of 189.5 per square mile (73.2/km). The racial makeup of the county was 90.4% white, 3.2% Asian, 2.1% black or African American, 0.2% American Indian, 2.1% from other races, and 2.0% from two or more races. Those of Hispanic or Latino origin made up 5.3% of the population.
Of the 155,466 households, 33.5% had children under the age of 18 living with them, 51.6% were married couples living together, 10.5% had a female householder with no husband present, 33.1% were non-families, and 25.3% of all households were made up of individuals. The average household size was 2.53 and the average family size was 3.05. The median age was 39.3 years.
For the period 2011–2015, 24.8% of the county’s population had French ancestry (including 9.9% of the total population with French Canadian ancestry), 20.9% had Irish, 13.1% had English, 10.2% had Italian, and 8.2% had German ancestry. For the same time period, the estimated median annual income for a household in the county was $71,244, and the median income for a family was $85,966. Male full-time workers had a median income of $60,349 versus $44,270 for females. The per capita income for the county was $35,242. About 5.8% of families and 8.8% of the population were below the poverty line, including 11.7% of those under age 18 and 5.9% of those age 65 or over.
Hillsborough County New Hampshire neighborhoods include: Emerald Lake Village Dist