Forty Fort, borough (1990 pop. 5,049), Luzerne co., NE central Pa., residential suburb 2 mi/3.2 km NNE of Wilkes-Barre, on Susquehanna R. (bridged). Light mfg. Settled 1772 on site of Colonial fort in the Wyoming Valley. Settlers made last stand here in Wyoming Valley massacre, 1778.