The brick building, which formed a 'U' around a central courtyard containing market sheds was constructed with great attention to technological advances in safety and strength.
It ran from a terminal in Georgetown, was carried across the Potomac River on an aqueduct near the current Key Bridge, then ran along the west side of the Virginia shore, crossed Four Mile Run on another aqueduct, entered Alexandria, and descended to the Potomac by means of three lift locks, lowering barges to the river at low tide.
The entire canal system was about seven miles long.
The school played a major role in Alexandria's free black community prior to the Civil War despite the state restrictions on the assembly of African Americans.
Its library was one of the first open to African Americans.
The five Alexandria Historic Districts listed on the National Register of Historic Places include the Old and Historic District, Fairlington, Parkfairfax, Rosemont and the Town of Potomac.