Eventually, only Summit and New Providence remained joined. During this period, Summit was part of Springfield Township, which eventually broke up into separate municipalities. Summit was called the 'Heights over Springfield' during the late 18th century and most of the 19th century, and was considered a part of New Providence. During the American Revolutionary War, Summit was known as 'Beacon Hill', because bonfire beacons were lit on an eastern ridge in Summit to warn the New Jersey militiamen of approaching British troops. The original name of Summit was 'Turkey Hill' to distinguish it from the area then known as 'Turkey' ( New Providence's original name until 1759). Summit's earliest European settlers came to the area around the year 1710. The region in which Summit is located was purchased from Native Americans on October 28, 1664.

According to Bloomberg, Summit ranked as the 70th highest-income place in the United States in 2017, 72nd in 2018 (with an average household income of $220,971), and 65th in 2019. Summit had the 16th-highest per capita income in the state as of the 2000 Census. Possible derivations of Summit's name include its location atop the Second Watchung Mountain the Summit Lodge, the house to which jurist James Kent moved in 1837 and which stands today at 50 Kent Place Boulevard and to a local sawmill owner who granted passage to the Morris and Essex Railroad for a route to 'the summit of the Short Hills'.

Originally incorporated as Summit Township by an act of the New Jersey Legislature on March 23, 1869, from portions of New Providence Township (now Berkeley Heights) and Springfield Township, Summit was reincorporated as a city on March 8, 1899. As of the 2020 United States census, the city's population was 22,719, an increase of 1,262 (+5.9%) from the 2010 census count of 21,457, which in turn reflected an increase of 326 (+1.5%) from the 21,131 counted in the 2000 census. The city is located on a ridge in northern- central New Jersey, within the Raritan Valley and Rahway Valley regions in the New York metropolitan area. Summit is a city in Union County, in the U.S.

Nj transit train times