The High Ledge Mine was known to exist as early as 1868. In 1880, two shafts were sunk into parallel veins on land owned by Thomas L. King. The southeast shaft went down 50 to 60 feet into a shoot of magnetite ore ranging from 6 to 20 feet wide. The high grade ore raised from here yielded an impressive 65 percent iron with 1 to 3 percent sulphur. The second shaft located 600 feet northwest was sunk 30 feet into a deposit 6 feet wide of similar quality.

In May of 1880, the mine became idle. In 1883, Joseph Wharton leased the mine and worked it only during the spring. The mine was reopened in 1911 by the High Ledge Mines Company and operated until 1912. During this time, High Ledge was one of a handful of iron mines still in operation in New Jersey.

1 2