CANONSBURG, a borough of Washington county, Penn sylvania, U.S.A., 17m. S.W. of Pittsburgh; on Federal highway 19, and served by the Pennsylvania railroad. The population in 192o was 10,632, and it was 12,558 in 193o. It is in a rich farming district, with coal-mines and gas-wells near by. The borough has important manufactures (steel, tin-plate, tin cans, pottery and novelties) with an output in 1925 valued at 892.