Puerto Rican 1.7% Swedish 1.6% Greek 1.2% Sub-Saharan African 1.2% Haitian 1.2% Armenian 1.1% Canadian 1.0% Cambodian 1.0% Arab Of the 580,688 households, 31.0% had children under the age of 18 living with them, 49.5% were married couples living together, 10.1% had a female householder with no husband present, 36.9% were non-families, and 27.8% of all households were made up of individuals. The average household size was 2.49 and the average family size was 3.10. The median age was 38.5 years. The median income for a household in the county was $77,377 and the median income for a family was $97,382. Males had a median income of $64,722 versus $50,538 for females. The per capita income for the county was $40,139. About 5.1% of families and 7.6% of the population were below the poverty line, including 8.0% of those under age 18 and 8.0% of those age 65 or over. 79.6% spoke English, 4.3% Spanish, 2.7% Portuguese, 1.6% Italian, 1.6% Chinese including Mandarin and other Chinese dialects and 1.5% French as their first language. Middlesex County has the largest Irish-American population of any U.S. county with a plurality of Irish ancestry. Demographic breakdown by town Income The ranking of unincorporated communities that are included on the list are reflective if the census designated locations and villages were included as cities or towns. Data is from the 2007-2011 American Community Survey 5-Year Estimates. Law enforcement The primary responsibility of the Middlesex Sheriff's Office is oversight of the Middlesex House of Correction and Jail in Billerica. It formerly ran the Middlesex Jail in Cambridge, which closed on June 28, 2014. In addition, the Sheriff's Office operates the Office of Civil Process and, the Lowell Community Counseling Centers, and crime prevention and community service programs. The office of sheriff was created in 1692, making it one of the oldest law enforcement agencies in the United States. The sheriff is elected to a 6-year term. Notable sheriffs include: Col. James Prescott (1775–1781) Col. Loammi Baldwin (1781–1794) Col. Samuel Chandler (1841–1851) Charles Kimball (1859–1879) John J. Buckley (1970–1980) John P. McGonigle (1985–1994) James DiPaola (1996–2010) John Granara (Special) (2010–2011) Peter Koutoujian (2011–Present) Politics Prior to 1960, Middlesex County was a Republican Party stronghold, backing only two Democratic Party presidential candidates from 1876 to 1956. The 1960 election started a reverse trend, with the county becoming a Democratic stronghold. This has been even more apparent in