Jefferson Pier Stone

In 1793, surveyors marked the intersection of a north–south line from the White House and an east–west line from the U.S. Capitol on the bank of Tiber Creek. First planted as a wooden post, it was replaced in 1804 by a stone pier intended as a local longitude reference for the capital. Workers grading the Washington Monument grounds inadvertently removed it in the 1870s, though its base survived. The present marker was erected directly above the recovered foundation in 1889, preserving a tangible trace of early federal surveying before national mapping shifted to the Old Naval Observatory.