The South Glens Falls hydroelectric project site has long played a key role in the local economy on the south side of the Hudson River beside the natural thirty-six-foot-high waterfall known as Glens Falls. Formed of Glens Falls limestone, a hard black rock that resists the wearing action of the water, the falls have powered a series of dams at this site since the mid-1700s. First settlers established mills here in the 1760s using the force of falling water, and over time industries on both sides of the river included lumber mills, gristmills, stone sawmills, factories making wood products such as window sashes, blinds, hubs, and spokes for wagon wheels, as well as lumber and plaster mills, lime kilns, and a paper mill on the south side. During the nineteenth and twentieth centuries, nearby deposits of Glens Falls limestone were mined and turned into building stone and Portland cement. By the late nineteenth and early twentieth centuries, papermills and generating plants on both sides of the Hudson River were using the falls to produce electricity. Today hydro generating plants on the north and south sides of the river continue that use of waterpower, and the South Glens Falls Facility, constructed in 1993-1994, includes a redeveloped dam with new crest gates, a new intake structure, two sixteen-foot-diameter penstocks, and a powerhouse with two new hydro generating units that provide enough electric power to meet the needs of eleven thousand homes.