The Custis Trail connects to the W&OD Trail and runs along I-66 towards the western part of Northern Virginia. The asphalt paved trail is four miles in length and connects commuters to Washington D.C. via the Key Bridge and Mount Vernon Trail. Because it is not a rails-to-trails conversion, there is considerable elevation change on the route, particularly at bridges and underpasses. The path is well used and cyclists and runners are not likely to be alone during the day. Water, benches, and trashcans are found at various points along the route, and the path is well marked, with signs indicating the distance to various cities. The trail has marked divided lanes and cyclists, pedestrians, and leashed pets are welcome. The Custis Trail is more shaded than the W&OD Trail, but can be crowded at rush hour when commuters utilize the route. Numerous entry points exist at various neighborhoods along the trail, and some street parking is available.