English: Lock and Dam Number 4 on the Allegheny River, Allegheny County, Pennsylvania, United States. Lock and Dam 4 was built from 1920-27, and opened in 1927.
{{Information |Description={{en|1=Lock and Dam Number 4 on the Allegheny River, Allegheny County, Pennsylvania, United States. Lock and Dam 4 was built from 1920-27, and opened in 1927.}} |Source=U.S. Army Corps of Engineers Digital Visual Library [http:
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