At the upper end of the Rockaway Valley, where the Rockaway River drops 25 feet, Rockaway developed as an excellent site for waterpowered industry. In the 1730s, early settler Job Allen built a bloomer forge on the river, and another early settler, Joseph Jackson, came from Long Island, built a cabin, and began acquiring property. In 1778 Joseph’s son Stephen purchased an interest in the forge and eventually acquired the entire operation. In 1796 he built a second forge downstream and, to supply ore and charcoal, purchased additional property including most of what would become the village of Rockaway. When Stephen Jackson died in 1812, he left a well established business of mines, forges, and a gristmill-sawmill powered by the river’s flow. His sons, Col. Joseph and William Jackson, upgraded the forges and expanded the family holdings to include a rolling mill beside the lower forge. The upper and lower forges together had five fires where ore was smelted into blooms, which were then hammered into billets; at the rolling mill, billets were reheated and rolled into bars for manufacturing iron products of many kinds. Water power ran bellows, trip hammers, and roller trains, with the river dammed in two places to form mill ponds feeding raceways and numerous water wheels, while the upper dam also supplied extra water for the gristmill-saw mill. Waterpower also had limits, as spring floods often washed away dams and summer droughts could halt work. By the 1890s, the New Jersey iron industry was in decline, and newer industries such as the Liondale Bleach, Dye & Print Works installed powerful steam engines and no longer depended on the river for motive power.