The arch carries the West Drive above while a narrow footpath runs under it, along the water. Designed by Calvert Vaux and Jacob Wrey Mould, Glen Span Arch was built in 1865. The original arch featured wooden trestles, rock pier supports, and a wooden railing. The arch was reconstructed about 20 years later, when the wooden components were replaced with the light-gray gneiss rock you see today.
The picturesque arch is made from rock blasted from the rock outcrops. To the west, visitors can hear the distinctive sound of a steep waterfall sending water from the Pool over a rocky incline.