Cooper & Hewitt partners were iron businessmen who purchased ironworks, property, and iron mines. The partnership of Cooper & Hewitt was formed in 1847 by Edward Cooper (1824-1905)--the son of New York City manufacturer and philanthropist Peter Cooper (1791-1883)--and his brother-in-law, Abram S. Hewitt (1822-1903). The partnership took over the management of the iron manufacturing facilities owned by the Cooper family. These included a rolling mill complex built by Cooper & Hewitt at Trenton, New Jersey, in 1845 and incorporated as the Trenton Iron Company two years later; blast furnaces at Philipsburg, New Jersey, built in 1847; mines at Ringwood, New Jersey, purchased in 1853; and the Durham Iron Works in Pennsylvania, purchased in 1870.

To secure a supply of good iron ore, Hewitt had purchased the abandoned iron mines at Andover, New Jersey, in 1847. The Andover mines had been extensively worked before the Revolution, and the government of New Jersey had seized the property from its loyalist owners to supply the Revolutionary armies. After the war the mines were mismanaged, and they were abandoned in 1800. Cooper & Hewitt also built the Sussex Mine Railroad in 1854, running from the mines to the Morris Canal, which carried the ore to the furnaces at Philipsburg. The Andover mines were nearly exhausted by 1862.