| Mount Vernon, Alexandria & Washington Railway | 1927 |
| Alexandria, Barcroft & Washington Rapid Transit | 1924 |
| Alexandria-Washington Buses, Inc. | 1931 |
| Washington-Virginia Railway | 1910 |
| Washington, Alexandria & Mount Vernon Railway merged into the W-V Ry | 1890 |
| Washington, Arlington & Falls Church Railway merged into the W-V Ry | 1891 |
| Columbia Pike Bus Line | 1921 |
| Alexandria Motor Bus Line | 1921 |
| Alexandria and Camp A.A. Humphrey Bus Line | 1922 |
| Alexandria-Washington Buses, Inc. | 1931 |
| Mount Vernon, Alexandria & Washington Railway | 1927 |
