Sligo Creek is a free-flowing tributary of the Northwest Branch of the Anacostia River; the stream joins the Northwest Branch at the western city limits of Hyattsville. The Sligo Creek watershed is generally bound by Arcola Avenue and University Boulevard to the north and east, Queen’s Chapel Road to the southeast, and the District of Columbia and Georgia Avenue to the west. Seventy-five percent of the watershed is in Montgomery County, with 20% and 5% in Prince George’s County and the District of Columbia, respectively.
The three largest land uses by area in the Sligo Creek watershed are residential (75%), forest cover (10%), and commercial (8%). The 2010 population of the Sligo Creek watershed was 81,943 (population density: 7,081/square mile.)
The Sligo Creek watershed is 7,085 acres (11.07 sq. mi.) in size. Approximately 33% of that area is pavement or other impervious surfaces. Elevations range from 450 feet at the sub-watershed divide to 35 feet at the confluence with the Northwest Branch. With an average gradient of 0.72% over 8.3 miles of the mainstem, Sligo Creek flows from its headwaters in the Piedmont physiographic province into the Coastal Plain. The entire lower mainstem, from Riggs Road to the confluence with Northwest Branch, has been channelized.