In the shadow of the Washington Monument is a small granite stone marking the site of the Jefferson Pier.
It puzzles tourists.
The stone marks the intersection of the latitude of the Capitol with the longitude of the White House. That intersection is marked on the top of the stone.
Jefferson had the meridian of the front door of the White House marked (along 16th Street) in hopes that it would become the prime meridian of the United States, the longitude from which distance and time in the U.S. would be measured, longitude 0' 0". He had the intersection of this meridian and the parallel of the Capitol marked with a blue stone structure covered with a flat top of Aquia sandstone on the edge of Tiber Creek. The 16th Street meridian never became the official prime meridian of the U.S.; the 24th Street meridian did. In 1884, the world recognized the longitude of Greenwich England as the prime meridian.
Its position on the 16th Street meridian places the Jefferson Pier due south of the White House and due north of the Jefferson Memorial.
In the 18th and 19th centuries, this spot was on the swampy shore of Tiber Creek, the lost river of DC that ran where the National Mall now stands. Since the 1870's, Tiber Creek has run in a huge sewer under the Mall. The Washington Monument was at first planned to be placed on this spot, but the ground was too soft, and the monument was placed in its current more stable position west of the 16th Street meridian. The original Jefferson Pier is visible in this 1850 drawing by Montgomery Miegs of the Washington Monument under construction.
The original pier was destroyed by the Corps of Engineers in the 1870's. The spot was recovered and the current monument put up in 1889. A line has been scrubbed out on the face of the stone.
Position of Jefferson
Pier Erected Dec. 1804,
Recovered and Re-Erected
District of Columbia
The missing words are "Being the Center Point of The." No one knows when the incorrect line was struck out, but this really isn't the center of the District.