Gateway of the Citadel, Stone entrance gate in Ciudad Vieja, Uruguay

The Gateway of the Citadel is the only surviving piece of the military fortress that defended the walled city of Montevideo. It is a stone portal with an arch flanked by two round towers, standing beside Plaza Independencia at the start of Ciudad Vieja. It was dismantled stone by stone and rebuilt in 1959 a few metres from its original position, on a new buttress structure.

The Citadel of Montevideo was a Spanish military fortress built in 1741 to defend the walled city by land; its gateway was the entrance to that fortress, not to the city walls, whose gates of Saint John and Saint Peter were demolished in 1829. The citadel was demolished in 1877, and the gate was dismantled stone by stone and reused at a technical school on Gonzalo Ramírez Street. In 1959 it was rebuilt a few metres from its original spot, aligned with Peatonal Sarandí, and restored again in 2009.

The gateway stands beside Plaza Independencia and marks the start of Ciudad Vieja, the city's oldest quarter. It is the only surviving piece of the Citadel of Montevideo, so it is often taken for the entrance of the old walled city, though that gate was a different one, demolished in 1829.

The gateway stands on the edge of Plaza Independencia, a few metres off the axis of Peatonal Sarandí, which it marks as the start of Ciudad Vieja. It is a freestanding portal with no steps or upper level, so it is seen at street level on foot; a support structure was built behind it in 1959 to hold the stones in place.

The gateway is often mistaken for the entrance to the walled city, but the city's two gates, Saint John and Saint Peter, were demolished in 1829 and are lost. This arch was the landward gate of the Citadel fortress, demolished in 1877; its stones were then moved to a technical school before returning in 1959.