both of which go toward Boston. Close to Boston, MBTA buses also exist. The MVRTA is a bus company that connects cities within the Merrimack Valley portion of Essex County. National protected areas Because of Essex County's rich history, which includes 17th century colonial history, maritime history spanning its existence, and leadership in the expansions of the textile industry in the 19th century, the entire county has been designated the Essex National Heritage Area by the National Park Service. The following areas of national significance have also been preserved: Parker River National Wildlife Refuge Salem Maritime National Historic Site Saugus Iron Works National Historic Site Thacher Island National Wildlife Refuge Demographics As of the 2010 United States Census, there were 743,159 people, 285,956 households, and 188,005 families residing in the county. The population density was . There were 306,754 housing units at an average density of . The racial makeup of the county was 81.9% White, 3.8% Black or African American, 3.1% Asian, 0.4% American Indian, 8.2% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 16.5% of the population. In terms of ancestry, 23.3% were Irish, 17.1% were Italian, 12.6% were English, 6.1% were German, and 3.6% were American. Of the 285,956 households, 32.9% had children under the age of 18 living with them, 47.9% were married couples living together, 13.5% had a female householder with no husband present, 34.3% were non-families, and 28.1% of all households were made up of individuals. The average household size was 2.54 and the average family size was 3.14. The median age was 40.4 years. The median income for a household in the county was $64,153 and the median income for a family was $81,173. Males had a median income of $58,258 versus $44,265 for females. The per capita income for the county was $33,828. About 7.7% of families and 10.1% of the population were below the poverty line, including 13.3% of those under age 18 and 9.4% of those age 65 or over. 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. Politics Education Essex County is home to numerous libraries and schools, both public and private. School districts School districts