Construction on the Summerhouse began in 1879 and was completed in late 1880 or early 1881 by landscape architect Frederick Law Olmsted. Olmsted had been appointed by Congress in 1874 to develop and improve the Capitol grounds, which had been enlarged in response to the addition of the north and south wings of the Capitol. He included the Summerhouse in response to complaints that visitors to the Capitol could find no water nor any place to rest on their journey.
Constructed to provide comfort for those who explore the area on foot, it is also a pleasant location from which to appreciate the Capitol's classical architecture and the landscaping that surrounds it.
The fountain in the center of the building originally provided drinking water piped from a spring. The six small metal fittings around the fountain's upper perimeter secured chains that are believed to have held drinking cups or ladles. Three individual drinking fountains connected to the filtered city water supply now provide drinking water, and the central fountain is used only for display.
Olmsted originally planned two Summerhouses for the Capitol Grounds; however, congressional objections to the northern Summer House before its completion prevented the construction of the southern one.