Sligo Creek is a free-flowing tributary of the Northwest Branch of the Anacostia River in Maryland. (The Anacostia, in turn, feeds into the Potomac River and eventually empties into the Atlantic Ocean via Chesapeake Bay.) The creek is approximately long, with a drainage area of about . Geography The creek rises in the Kemp Mill section of Silver Spring in Montgomery County and joins with Northwest Branch near the city of Hyattsville in Prince George's County. The lower portion of the creek has been channelized. Elevations in the subwatershed range from above sea level to at the confluence with Northwest Branch; the average gradient for the course of the creek is 0.72%. Contributing streams that flow into the creek include Wheaton Branch, Comstock Branch, Takoma Park Branch, and Long Branch. Sligo Creek is one of the most heavily urbanized subwatersheds in the Anacostia watershed, with a population density of 7,081 people per mi2. 75% of the watershed is in Montgomery County, 20% is in Prince George's County, and 5% is in the District of Columbia. Less than 15% of the subwatershed is undeveloped, and only 10% is forested. Less than 0.01% of the area is wetlands. From its source to the confluence with the Northwest Branch, the creek crosses through the communities of Silver Spring, Wheaton, Takoma Park, Carole Highlands, Chillum and Hyattsville. In these towns, the banks of the creek are in many stretches maintained as public parkland, with grassy lawns and playing fields. The Sligo Creek Trail, a hiker-biker trail, runs along the creek from Wheaton to the confluence, where it connects with the Anacostia Tributary Trail System. An automobile parkway runs along many parts of the creek in Montgomery County. Pollution and stream restoration The Sligo Creek watershed is a highly urbanized area, and as a result the water quality in the creek and tributaries is degraded. In 2002 the Maryland Department of the Environment (MDE) classified the creek as having poor water quality. The Montgomery County Government began installing several stormwater management and stream restoration projects in the watershed in 1989, and by 2009 MDE had recognized some improvements in stream quality. Additional county projects are ongoing as of 2018. History Sligo Creek was named after the crossroads named "Sligo" founded in the mid 19th century by Irish immigrant workers on the C&O Canal. It may have been named after County Sligo in Ireland. The crossroads