From the Baseline Report – The State of Bicycling in Arlington

In September, 1967, Arlington County constructed its first bicycle facility, a paved multi-use trail along about three miles of the Four Mile Run stream valley Development of this ever-enlarging network of bicycle facilities has been directed by a series of bicycle planning documents beginning with the May 1974 Master Bikeway Plan. That plan called for an 80-mile network of interconnected trails for commuter and recreational use, established overall goals and objectives, and presented a design guide.

Currently there are "50 miles of off-street trails, another 77 miles of on-street facilities such as bicycle lanes, bicycle boulevards and routes"