By 1900, the lumber industry had declined, and the city's economic base rested on other industries, including a furniture factory, a paper mill, a fire brick plant, and a silk mill. In 1938, the Piper Aircraft Corporation, maker of the Piper Cub and other light aircraft, moved its production plant to Lock Haven. It remained one of the city's biggest employers until the 1980s, when, after major flood damage and losses related to Hurricane Agnes in 1972, it moved to Florida. The loss of Piper Aircraft contributed to an unemployment rate of more than 20% in Lock Haven in the early 1980s, though the rate had declined to about 9% by 2000. Another large plant, the paper mill that had operated since the 1880s in Castanea Township, closed in 2001. By 2005, 32% of the city's labor force was employed in health care, education, or social services, 16% in manufacturing, 14% in retail trade, 13% in arts, entertainment, recreation, accommodation, and food services, and smaller fractions in other sectors. The city's biggest employers, Lock Haven University of Pennsylvania and UPMC Susquehanna Lock Haven hospital, are among the seven biggest employers in Clinton County.
