Formed March 7, 1683 (4th county)
Middlesex County (863,183), New Brunswick (55,252), Perth Amboy (55,444)
The Modern glass and marble courthouse was built in 1958. It is located on Paterson Street at Elm Row. New Jersey State Highway 18 is five blocks northeast of the location. The architect is unknown. There was an 1840 courthouse earlier in New Brunswick. Perth Amboy was the county seat until 1793. A Family Courthouse was added in 2000. Middlesex County was one of the original counties (4th county) created on March 7, 1683. The county is named for Middlesex County, England. The county seat is named for the Duke of Brunswick. Middlesex County was the birthplace for 4 New Jersey Governors, Joseph Bloomfield, George S. Silzer, Morgan F. Larson, and Harold G. Hoffman.
Middlesex County government consists of an executive, a sheriff, an administrator and a clerk (executive). It has 7 Commissioners (legislative.) Thirty-one Superior Court Judges and a prosecutor serve Middlesex County (judicial.) Middlesex County is in northeast New Jersey bordering New York. Newark, New Jersey is north and New York, New York is northeast of the county. The county center is 8.5 miles Southeast of New Brunswick in Old Bridge. The county is surrounded clockwise by Union County, and New York, and Monmouth, Mercer, and Somerset counties.
The area of the county is 311 square miles. It is 12 out of 21 in the state. It ranks 2 out of 21 in population in the state. It has a density of 2775.5 persons per square mile making it 6 out of 21 in the state. Middlesex County has 35.6% of its population in its incorporated areas. Interstate Highway 95 crosses the county northeast to southwest from Union County to Mercer County. United States Highway 1 goes northeast to southwest from Union County to Mercer County. United States Highway 9 enters from Monmouth County, east, and joins United States Highway 1 into Union County. United States Highway 130 parallels Interstate Highway 95 from Union to Mercer counties. The county looks like a bear cub tilted 45 degrees northeast. New Brunswick is located in the northwest corner of the county. New Brunswick is the county seat and Perth Amboy is the largest city. New Brunswick is 6.4% of the county population while Perth Amboy is 6.4. This county is in the New York-Northern New Jersey-Long Island Metropolitan Statistical Area.
Carteret
Dunellen
Helmetta
Highland Park
Jamesburg
Metuchen
Middlesex
Milltown
New Brunswick
Perth Amboy
Sayreville
South Amboy
South Plainfield
South River
Spotswood