When the District of Columbia was founded in 1790, the Potomac River was much wider than it currently is, and a major tidal estuary known as Tiber Creek flowed roughly from 6th Street NW to the shore of the river (then just south of the White House). In Pierre (Peter) Charles L'Enfant's original plan for the city in 1791, B Street NW began at 6th Street NW, and ended at the river's edge at 15th Street NW. Its eastern segment, which was unimpeded by any water obstacles, ran straight to the Eastern Branch river (now known as the Anacostia River). Along its entire length, B Street was wide.