|Waterway||Chesapeake and Ohio Canal|
The Tidewater Lock is a dam in Washington, D.C. to the west of the mouth of Rock Creek at the Potomac River, on the east side of Georgetown. It is sometimes listed as Lock 0 on the Chesapeake and Ohio Canal. On historical canal documents, this is listed as "Tide Lock A".
Canal Documents sometimes list a "Tide Lock B" on section "I" which stood at the lockhouse at 17th and Constitution Ave NW. It was completed in 1834.