Middlesex County is a county located in the central portion of the U.S. state of New Jersey,Governor Murphy Settles Central Jersey Debate, Governor of New Jersey Phil Murphy, press release dated August 4, 2023. "Governor Phil Murphy today signed S3206 to promote Central Jersey tourism.... The 'Central Jersey' region will be comprised of, at minimum, the counties of Hunterdon, Mercer, Middlesex, and Somerset."Willis, David P. "'This is how wars start': Does Central Jersey include both Ocean and Union counties?", Asbury Park Press, February 20, 2023. Accessed March 31, 2024. "North Jersey is defined as Sussex, Warren, Morris, Passaic, Bergen, Essex and Hudson counties; South Jersey would be Burlington, Camden, Gloucester, Atlantic, Salem, Cumberland and Cape May counties. But for Central, things get a little tricky. It would include Hunterdon, Somerset, Union, Middlesex, Mercer, Monmouth, and Ocean counties.""Regions: North, Central, South, Shore - Best of NJ", Best of NJ, Accessed May 30, 2024. "Central Jersey consists of Hunterdon, Mercer, Middlesex, Somerset, and Union County." extending inland from the Raritan Valley region to the northern portion of the Jersey Shore. As of the 2020 United States census, the county was the state's third-most populous countyAnnual and Cumulative Estimates of Resident Population Change for Counties in New Jersey and County Rankings: April 1, 2020 to July 1, 2021, United States Census Bureau. Accessed June 1, 2022. with a population of 863,162, its highest decennial count ever and an increase of 53,304 (+6.6%) from the 2010 census count of 809,858, which in turn reflected an increase of 59,696 (8.0%) from the 750,162 counted in the 2000 census.Wu, Sen-Yuan. NJ Labor Market Views: Population Keeps Growing in the Most Densely Populated State, March 15, 2011. Accessed December 26, 2022. The United States Census Bureau's Population Estimates Program estimated a 2025 population of 883,335, an increase of 20,173 (+2.3%) from the 2020 decennial census. The county seat of Middlesex is the city of New Brunswick,New Jersey County Map, New Jersey Department of State. Accessed January 20, 2024. a center for the sciences, arts, and cultural activities, and the headquarters of the state's flagship academic institution, Rutgers University.New Brunswick, NJ: Yesterday, Today, Tomorrow, Rutgers University Libraries. Accessed January 20, 2024. "New Brunswick is the county seat of Middlesex County, New Jersey, and is also the home of Rutgers University–New Brunswick." The county forms part of the New York metropolitan area. Middlesex County calls itself The Greatest County in the Land.

The county is located in the middle of the Northeast megalopolis of the U.S. The county's most populous place, with 107,588 residents as of the 2020 census, is Edison,QuickFacts Edison township, Middlesex County, New Jersey Accessed January 4, 2024. while Monroe Township covers the largest area of any municipality, at .2019 Census Gazetteer Files: New Jersey Places, United States Census Bureau. Accessed January 4, 2023. Since the 2010 census, the state's center of population is in East Brunswick; the center of population for New Jersey has been in Middlesex County since the 1900 census.Sweilem, Amira. "N.J.’s population center still tilts north. This town considers it a badge of honor.", NJ Advance Media for NJ.com, November 27, 2022. Accessed January 20, 2024. "Answer time: East Brunswick has held the statistical center of population title since the 2010 Census.... The U.S. Census runs the calculation every 10 years and it has wobbled around Middlesex County since 1880, straying just once since that time into Somerset County (Warren Township) in 1890. East Brunswick just barely held onto the population center in the 2020 Census calculations.... The new spot is on Hawk Court just off Milltown Road between the NJ Turnpike and Ryders Lane." Middlesex County hosts an extensive transportation network, including several rail stations along the heavily traveled Northeast Corridor Line of the New Jersey Transit commuter rail system, as well as the intersection of the New Jersey Turnpike and the Garden State Parkway, the state's two busiest motor vehicle roadways, in Woodbridge Township. Many towns within Middlesex County serve as commuter towns to New York City, as well as to employment centers in Jersey City, Newark, and other points in North Jersey.

The county was primarily settled due to its optimal location along the Raritan River.History , Middlesex County, NJ. Accessed March 24, 2018. Middlesex was originally formed as one of four administrative districts within Province of East Jersey in 1675, together with Bergen, Essex and Monmouth districts. Middlesex County was formed within East Jersey on March 7, 1683.Snyder, John P. The Story of New Jersey's Civil Boundaries: 1606–1968, Bureau of Geology and Topography; Trenton, New Jersey; 1969. p. 125. Accessed June 6, 2012. The population increased so the county was partitioned on October 31, 1693, into the townships of Piscataway, Perth Amboy, and Woodbridge. Adjacent Somerset County was established on May 14, 1688, created from portions of Middlesex County.

The county's first court met in June 1683 in Piscataway, and held session at alternating sites over the next century in Perth Amboy, Piscataway, and Woodbridge before relocating permanently to New Brunswick in 1778.History of the Grand Jury , Middlesex County, New Jersey. Accessed October 1, 2013. "By June 19, 1683, the first County Court was held at Piscataway. It sat alternately in Piscataway and Woodbridge until 1688 when Perth Amboy was added as one of the three alternate sites. In 1778, New Brunswick became the most prime town in the county and at that time the Middlesex County Courts were transferred there." Despite its status as a residential, commercial, and industrial stronghold and a centrally accessible transportation hub, Middlesex is also home to an extensive public park system with expansive greenways, totaling more than . Middlesex County is most demographically notable as the U.S. county with the highest concentration of Asian Indians, at nearly 20% in 2020, spanning the county's boundaries between Little India, Edison/Iselin in the north and Monroe Township at its southern tip.

Geography and climate Middlesex has a hot-summer humid continental climate (Dfa) which borders a humid subtropical climate (Cfa) on Raritan Bay and Arthur Kill. Average monthly temperatures in downtown New Brunswick range from in January to in July, while in South Amboy they range from in January to in July.Time Series Values for Individual Locations, Oregon State University. Accessed June 24, 2023. In recent years, average temperatures in the county seat of New Brunswick have ranged from a low of in January to a high of in July, although a record low of was recorded in January 1984 and a record high of was recorded in July 1999. Average monthly precipitation ranged from in February to in July.

According to the U.S. Census Bureau, as of the 2020 Census, the county had a total area of , of which was land (95.8%) and was water (4.2%).2020 Census Gazetteer File for Counties in New Jersey, United States Census Bureau. Accessed April 1, 2023. The county is named after the historic English county of Middlesex.Kane, Joseph Nathan; and Aiken, Charles Curry. The American Counties: Origins of County Names, Dates of Creation, and Population Data, 1950-2000, p. 202. Scarecrow Press, 2005. . Accessed January 22, 2013.

Bisected by the Raritan River, the county is topographically typical of Central Jersey in that it is largely flat. The majority of the county is located on the inner coastal plain, with the remainder of the county being located on the Eastern Piedmont. The elevation ranges from sea level to above sea level on a hill scaled by Major Road/ Sand Hill Road near Route 1 in South Brunswick Township.New Jersey County High Points , Peakbagger.com. Accessed October 5, 2013.

Another area with higher elevation in the county is the Perth Amboy Moraine, left by the southern limit of the Laurentide Ice Sheet. Only the far northeastern area of the county was glaciated, and the Perth Amboy Moraine stretches from Perth Amboy, through Woodbridge, Edison and Metutchen, and stradles the border of Edison and South Plainfield before exiting the county. The area includes peaks of over 200 feet.

Demographics

Indian community Middlesex County is prominently known for its significant concentration of Indians. The growing Little India is a Desi-focused commercial strip in Middlesex County, the U.S. county with the highest concentration of Indians. The Oak Tree Road strip runs for about one-and-a-half miles through Edison and neighboring Iselin in Woodbridge Township, near the area's sprawling Chinatown and Koreatown, running along New Jersey Route 27. It is the largest and most diverse Desi cultural hub in the United States. Monroe Township in Middlesex County has experienced a particularly rapid growth rate in its Indian American population, with an estimated 5,943 (13.6%) as of 2017,DP05: ACS DEMOGRAPHIC AND HOUSING ESTIMATES from the 2013-2017 American Community Survey 5-Year Estimates for Monroe township, Middlesex County, New Jersey , United States Census Bureau. Accessed February 11, 2019. which was 23 times the 256 (0.9%) counted as of the 2000 Census; and Diwali is celebrated by the township as a Hindu holiday. Carteret's Punjabi Sikh community, variously estimated at upwards of 3,000, is the largest concentration of Sikhs in New Jersey. In Middlesex County, election ballots are printed in English, Spanish, Gujarati, Hindi, and Punjabi.

Jewish community Along with other counties in New Jersey, Middlesex is also home to a large Jewish community, especially Orthodox. The world's largest Jewish gathering outside of Israel occurred in Edison on December 1, 2024.

2020 census

As of the 2020 census, the county had a population of 863,162, a median age of 38.8 years, 21.2% of residents under the age of 18, and 15.2% of residents aged 65 years or older; for every 100 females there were 95.9 males, and for every 100 females age 18 and over there were 93.6 males age 18 and over. Those residents lived in 300,547 households, including 209,808 families, resulting in a population density of and 315,521 housing units at an average density of . 4.7% of the housing units were vacant, and of the occupied units 61.8% were owner-occupied while 38.2% were renter-occupied; the homeowner vacancy rate was 1.1% and the rental vacancy rate was 5.5%. 34.8% of households had children under the age of 18 living with them, 54.1% were married couples living together, 15.6% had a male householder with no spouse or partner present, and 25.1% had a female householder with no spouse or partner present. About 22.2% of all households were made up of individuals, 9.7% had someone living alone who was 65 years of age or older, the average household size was 2.80, and the average family size was 3.32. The county's racial makeup was 41.9% White, 9.8% Black or African American, 0.5% American Indian and Alaska Native, 26.5% Asian, <0.1% Native Hawaiian and Pacific Islander, 12.2% from some other race, and 9.1% from two or more races. Hispanic or Latino residents of any race comprised 22.4% of the population. 99.0% of residents lived in urban areas, while 1.0% lived in rural areas. The county's median household income was $93,418, and the median family income was $107,149. About 8.8% of the population were below the poverty line, including 11.1% of those under age 18 and 8.8% of those age 65 or over.

Racial and ethnic composition