Ohio River, 341.0 miles below Pittsburgh, PA, and 5.0 miles below Greenup, KY. Replaced locks and dams Nos. 27,28,29 and 30 on Ohio River and No. 1 on Big Sandy River.

Non-navigable, high-lift, moveable gated dam, top length 1,287ft, including 245-foot fixed weir with 223-foot open crest. Nine tainter gates, clear span 100ft between 14-foot intermediate piers and 15-foot end piers, damming height 35ft above sills, clearance above maximum high water when fully raised approximately 5ft. The dam gates are non-submergible ogee sill units.

Of 3,258 acres in the project, approximately 166 acres fee required for the lock site, 45 acres fee for the abutment sites, 96 acres fee for recreation sites, 305 acres pondage easements were assigned to the Chesapeake & Ohio Railway Company and State Highway Department and Armco Steel Corporation and the City of Ashland, Kentucky, and Stowage easements or other lesser interests over the remaining area. In addition, 11.38 acres fee reassigned from old lock and dam sites.

The City of Hamilton, Ohio operates the hydroelectric plant of the Ohio abutment of Greenup Dam. The plant includes three turbines with total capacity of 70,000 kilowatts. The Federal Energy Regulatory Commission issued License Number 2641 for the project on 29 March 1976. The project was placed in commercial operation on 7 December 1982. The entire generating structure is a watertight, steel-plate enclosure constructed in dry dock at St. Nazaire, France. The structure was shipped across the Atlantic Ocean, unloaded and towed to the site via the Mississippi and Ohio Rivers.

Two parallel locks, main lock 110ft by 1,200ft, auxiliary lock 110ft by 600ft, miter service gates, vertical-lift emergency gates.

Normal upper pool elevations 515.0 feet m.s.l., upper pool length 61.8 miles to Robert C. Byrd Locks & Dam, normal upper pool surface area 11,200 acres, nominal lower pool elevation 485.0 feet m.s.l., (upper pool of Captain Anthony Meldahl Dam), normal lift 30.0 feet.

No extensive relocations necessary, but remedial measures required to adapt certain facilities to new pool conditions. Facilities include railroad and highway drainage structures and embankment slopes, municipal sewer outtakes and water intakes, pipe lines, power and communication lines, and waterway terminals.

Construction began in October 1954. The locks were initiated in October 1955 and were placed in operation 27 November 1959. Construction of the dam began in June 1958 and the pool was raised to full height 4 June 1962.