The first Carnegie library to open in the United States was in Braddock, Pennsylvania, about 9 miles up the Monongahela river from Pittsburgh. In 1889 it was also the site of one of the Carnegie Steel Company's mills. It was the second Carnegie Library in the United States to be commissioned, in 1887, and was the first of the four libraries which he fully endowed. An 1893 addition doubled the size of the building and included the third Carnegie Music Hall in the United States.