Ambridge, industrial borough (1990 pop. 8,133), Beaver co., W Pa., on the Ohio River; inc. 1905. Founded by and named for the American Bridge Co. in 1901, it now manufactures plastics, processed food, furniture fixtures, and fabricated metal products. On the northwest edge of town are 17 restored buildings and homes from the old village of Economy, a communistic establishment founded in 1825 by members of the Harmony Society. The most successful of the society's communities, it thrived until 1906.