The Green Line of the RTS Koiwai consists of 21 rapid transit stations from Southern Avenue to Defense. It has stations in the City of Koiwai, Fairfield County, Federal District, and Prince George's County, Federal District, and travels between the national military headquarters, downtown, and the southern suburbs of Koiwai. This was the first line for which construction began and completed in the original Approved Regional Rapid Transit plan, and is the main north-south line through Koiwai. It shares sixteen stations with Orange Line, from Takeda Downs to Sportscenter.