Constitution Avenue is a major east–west street in the northwest and northeast quadrants of the city of Washington, D.C., in the United States. It was originally known as B Street, and its western section was greatly lengthened and widened between 1925 and 1933. It received its current name on February 26, 1931, though it was almost named Jefferson Avenue in honor of Thomas Jefferson. Constitution Avenue's western half defines the northern border of the National Mall and extends from the United States Capitol to the Theodore Roosevelt Bridge. Its eastern half runs through the neighborhoods of Capitol Hill and Kingman Park before it terminates at Robert F. Kennedy Memorial Stadium. Many federal departmental headquarters, memorials, and museums line Constitution Avenue's western segment. Creating B Street 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 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. L'Enfant proposed turning Tiber Creek into a canal. His plan included cutting a new canal south across the western side of the United States Capitol grounds and converting James Creek, which ran from the Capitol south-southwest through the city, into the canal's southern leg. The Washington Canal Company was incorporated in 1802, and after several false starts substantial work began in 1810. The Washington City Canal began operation in 1815. The canal suffered from maintenance problems and economic competition almost immediately. Traffic on the canal was adversely affected by tidal forces, which the builders had not accounted for, which deposited large amounts of sediment in the canal. At low tide, portions of the canal were almost dry. After the Baltimore and Ohio Railroad built Washington Branch into the city in 1835, competition from railroads left the canal economically unviable. Although the Washington City Canal remained in use after the coming of the railroad, by 1855 it had filled with silt and debris to the point where it was