Elizabeth Locks &amp; DamElizabeth Locks &amp; Dam Elizabeth Locks & Dam Elizabeth Locks & Dam is one of nine navigational structures on the Monongahela River between Pittsburgh, Pennsylvania and Fairmont, West Virginia. Maintained and built by the U.S. Army Corps of Engineers, the gated dam forms an upstream pool that extends for 23.8 miles, stretching to Charleroi, Pennsylvania. The dam is located at mile 23.8 of the Monongahela River; it was modernized during a major reconstruction project in 1979-80. See also. List of crossings of the Monongahela River Elizabeth Locks & Dam Elizabeth Locks & Dam is one of nine navigational structures on the Monongahela River between Pittsburgh, Pennsylvania and