Jefferson Pier Stone

The Jefferson Pier Stone is a historic granite monolith on the National Mall in Washington, D.C., that marks the second prime meridian of the United States, although it was never officially recognized by Congress or the president. The stone marker, about 3 feet tall and 2.3 feet wide (0.9 by 0.7 meters), sits almost exactly south of the White House and west of the Capitol. Lines of longitude and latitude are engraved on its surface, while the west face bears an inscription noting its placement in 1804 and its restoration in 1889. A line that originally appeared on the stone, wrongly describing it as the center point, was later chiseled away.

The stone's history goes back to the planning of the capital. Thomas Jefferson, then Secretary of State, wanted scientific independence from Europe and commissioned a survey for a new prime meridian. In 1804, as president, he had a new line run south from the center of the White House, meeting a line running west from the Capitol. The stone was set at this intersection, originally intended to stand on the spot where an equestrian statue of George Washington was later planned. During construction of the Washington Monument, the stone served as an anchor point and reference mark; it was then nearly removed entirely during cleanup work in the 1870s and was not reset on its old foundation until 1889.

Today the stone is maintained by the National Park Service and sits on a north-south line that also takes in the Jefferson Memorial, completed in 1943. Although the official U.S. prime meridian was later shifted to the old Naval Observatory and eventually to Greenwich, the Jefferson Pier remains a fascinating relic of the city's early surveying history. You can see the plain granite block on the open grounds of the National Mall, where it stands as a silent witness to the urban planning and political ambitions of the Founding Fathers.