American Bridge attracted thousands of immigrants who came to fulfill their dreams of work, freedom, and peace. The steel mills became the focal point of the town. Most of the employees were relatives of relatives and the small town grew, with wards separating the town into ethnic sections.
With the growth of the steel mills, Ambridge became a worldwide leader in steel production.[citation needed] The borough became known for bridge building, metal molding, and the manufacture of tubes (large iron pipes). During World War II, the American Bridge Company fabricated steel for the building of LSTs (Landing Ship Tanks). The steel was then sent by rail to the adjacent American Bridge naval shipyard in Leetsdale, PA where the LSTs were built. The area was also home to several other steel mills like Armco, the pipe mill which manufactured oil piping, and A.M. Byers, a major iron and tool fabricator. Eventually competition by foreign steel producers began to cause the share of the steel market for U.S. manufacturers to dwindle. With the shift of steel production overseas, the Ambridge Bridge Company ended operations in Ambridge in 1983. The legacy of American Bridge can be seen today from coast to coast, from the Golden Gate Bridge in San Francisco to the Brooklyn Bridge in New York.