However, the area reverted to Bergen County in 1852 and became known as Union Township.Part of the region was known as Boiling Springs for a powerful and ceaseless spring located in the vicinity.There were 6,949 households out of which 29.8% had children under the age of 18 living with them, 52.8% were married couples living together, 10.4% had a female householder with no husband present, and 32.9% were non-families.
When Hudson County was formed in 1840, the area that is today North Arlington, Lyndhurst, Rutherford and East Rutherford became part of Harrison Township (of which today's remaining portion is Harrison town).
Despite its name, the spring actually consisted of cold groundwater seeps rather than hot springs.
The Erie Railroad built its Main Line from Jersey City across the Meadowlands in the 1840s.
The racial makeup of the borough was 77.57% (14,010) White, 2.92% (527) Black or African American, 0.07% (13) Native American, 13.08% (2,362) Asian, 0.01% (1) Pacific Islander, 3.68% (664) from other races, and 2.68% (484) from two or more races.
Hispanic or Latino of any race were 14.08% (2,543) of the population.