Split Rock Iron Furnace

The Split Rock Iron Furnace is an abandoned pig iron furnace located in Morris County, New Jersey.

The Split Rock Iron Furnace is an abandoned pig iron furnace located in Morris County, New Jersey. It was the last charcoal-fired furnace built in the state. 1

In 1862, Andrew B. Lyon oversaw the construction of the Split Rock Furnace for Hon. Andrew B. Cobb of Parsippany. 2 3 Cobb, the son of Colonel Lemuel Cobb, a well-known surveyor for the Board of Proprietors, inherited and purchased large tracts of land in the northern part of the county. 3 He also owned the Split Rock Iron Mine.

The newly built Split Rock Furnace featured a 32-foot-high stack with a bosh of unspecified dimensions. 1 Fueled by charcoal, its hot air blast was powered by a steam engine, with a daily production capacity of unspecified tons. At full production, the furnace consumed approximately one acre of woodland daily for fuel within the 3,000-acre Splitrock tract, including forges, mines, and a village.

By the time the furnace was completed, Cobb had realized the mistake of building it to operate solely on charcoal. 2 Anthracite coal-fueled furnaces had been in use for 20 years and were more cost-efficient. Nonetheless, Cobb believed the furnace could still be profitable using charcoal.

After Cobb’s death in 1873, his land holdings were inherited by his son, Andrew Lemuel Cobb. 2 The furnace was then closed, and the property was sold to the Montclair Water Company in 1896. In 1947-48, a dam was constructed immediately upstream of the furnace to transform Splitrock Pond into a large reservoir to supplement Boonton’s reservoir.



  1. Herold, Patricia. “Blue Acres.” Skylands Visitor.
  2. Butler, Kathleen. “Uncovering N.J.: Near the banks of Splitrock Reservoir, a rare blast from the past remains.” Jersey’s Best, 15 Mar. 2022.
  3. Split Rock Furnace.” History of Morris County, W. W. Munsell & Co., 1882, p. 56, .

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