The Silver Line is an extension of the Washington Metro subway system consisting of 29 subway stations from Route 772 in Loudoun County to Largo Town Center in Prince George's County, Maryland. The line will have stations in Loudoun, Fairfax, and Arlington counties in Virginia, and the District of Columbia. Eighteen stations will be shared with the Orange Line, including all thirteen shared between the Orange and Blue Lines from Rosslyn to Stadium-Armory.