HillsboroughCounty is the most populous county in the U.S. state of New Hampshire. As of 2010, the population was 400,721. Its county seats are Manchester and Nashua. Hillsborough is northern New England’s most populous county as well as its most densely populated.
Hillsborough was one of the five original counties identified for New Hampshire in 1769, and was named for Wills Hill, the Viscount Hillsborough who was British Secretary of State for the Colonies at the time. The county was organized at Amherst on March 19, 1771. In 1823 a number of towns were removed to become part of MerrimackCounty. Over several years ending in 1869, county administrative functions were moved from Amherst first to Milford in 1866 then to the current seats of Manchester and Nashua.
According to the U.S. Census Bureau, the county has a total area of 892 square miles, of which 876 sq is land and 16 sq mi (1.78%) is water. The highest point in Hillsborough county is PackMonadnock Mountain at 2,290.
National protected area
Wapack National Wildlife Refuge
As of the census of 2010, there were 400,721 people, 155,466 households, and 103,959 families residing in the county. The population density was 458 people per square mile. There were 166,053 housing units at an average density of 190 per square mile. The racial makeup of the county was 90.4% White, 2.1% Black or African American, 0.2% American Indian or Alaska Native, 3.2% Asian, 0.03% Pacific Islander, 2.1% from some other race, and 2.0% from two or more races. 5.3% of the population were Hispanic or Latino of any race.
There were 155,466 households, out of which 31.0% 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, and 33.1% were non-families. 25.3% of all households were made up of individuals and 8.4% had someone living alone who was 65 years of age or older. The average household size was 2.53 and the average family size was 3.05. In the county the population was spread out with 23.5% under the age of 18, 8.6% from 18 to 24, 26.7% from 25 to 44, 29.5% from 45 to 64, and 11.9% who were 65 years of age or older. The median age was 39.3 years.
For every 100 females there were 97.83 males. For every 100 females age 18 and over, there were 95.86 males. As of the 2010 American Community Survey, it was estimated that 22.2% of the population were of Irish, 16.7% French, 9.6% French Canadian, 14.4% English, 10.4% Italian, 8.1% German, 4.8% Polish, 3.7% Scottish, 3.6% American, and 2.6% Greek ancestry. 87.3% spoke English at home, 3.9% Spanish, and 6.3% some other Indo-European language. The median income for a household in the county was $68,312, and the median income for a family was $79,728. The per capita income for the county was $33,406. About 5.5% of families and 7.1% of the population were below the poverty line, including 10.4% of those under age 18 and 5.9% of those aged 65 or over.
Long the most populated county in New Hampshire, HillsboroughCounty has played a vital role in shaping the state’s politics as a whole, although it has shifted in its own leanings over the years. Historically a Republican county going back to the 19th century, the county’s more urban population made it receptive to Democrats in the early 20th century at a time when much of New England was solidly Republican. The county- and the state as a whole- voted Republican in every election since the founding of the Republican Party in 1856 until 1912, when both the county and the state were won by Democrat Woodrow Wilson. Four years later, Wilson’s margin of victory in HillsboroughCounty enabled him to narrowly win the state as a whole despite losing the majority of counties, and making New Hampshire the only state to vote Democratic in New England and the entire Northeast in 1916.
In 1928, Hillsborough was the only county in New Hampshire to vote for Democrat Al Smith over Republican Herbert Hoover, and in the 1930s Franklin Roosevelt would solidify Democratic dominance there. In 1936, FDR would carry only 3 of New Hampshire’s 10 counties, but his strong win in Hillsborough allowed him to narrowly win the state while neighboring Vermont and Maine were the only states in the nation to vote against him. In the 1940s, Roosevelt would take over 60% of the vote HillsboroughCounty, allowing him to win the state of New Hampshire by more comfortable margins in 1940 and 1944. The county would vote Democratic in every presidential election that followed until the 1970s, except for a win by Dwight D. Eisenhower in 1956, although it was still the only county in the state where Eisenhower failed to break 60% of the vote.
In the 1970s, shifting partisan allegiances and the growth of conservative Boston exurbs in southern New Hampshire caused a dramatic shift in HillsboroughCounty’s politics, which also caused the state as a whole to become more conservative. Beginning in 1972, the county became reliably Republican in presidential elections, peaking in 1984, when Ronald Reagan would take over 70% of the vote there. Although still one of the more Republican regions of the state, in the following years Democrats have made inroads and today it is an important swing county. Both Republicans George H.W. Bush and George W. Bush would win it twice each, but Democrat Bill Clinton won it in 1996, and Barack Obama has won it twice in both 2008 and 2012, bolstering his wins of the state’s electoral votes each time. In the 2012 presidential election, Time had listed Hillsborough as one of five critical counties affecting the outcome in the swing state of New Hampshire. Obama ended up winning with a margin of 50%-48%.