With construction beginning in the 1960s, I-77 would gain additional mileage in October 1964 when a two-mile (3 km) extension was granted by the U.S. Bureau of Public Roads. Instead of ending at I-85, I-77 now ended at Independence Boulevard (U.S. 74) in downtown Charlotte. Another extension was granted in the late 1960s that extended I-77 from Independence Boulevard to the South Carolina border. The latest extension also included a relocation of U.S. 21 from the city's surface streets to the new interstate.