U.S. Capitol Gatehouses and Gateposts in the context of "United States National Arboretum"

Aquia Creek sandstone is a brown to light-gray freestone used extensively in building construction in Washington, D.C. in the late 18th and early 19th centuries. Quarried at Aquia Creek in Stafford County, Virginia, the stone was valuable for its ease of shaping and the quarry's proximity to the tidewater portion of the Potomac River, 45 miles (72 km) south of Washington.

The sandstone was the principal material used in such significant buildings as the White House and the early stages of the U.S. Capitol. The easy availability of the stone and its ability to be carved were offset in time by its susceptibility to weather-induced deterioration. Its best, most enduring uses were as interior decorative elements.