Mile: 23 - 24

The access point for mile 23 is Riley's Lock at mile 22.8. From River Road, turn onto Riley's Lock Road and follow it to the end, where there is a parking lot. The lock coincides with the Seneca Creek Aqueduct. This part of the canal is also accessible via Tschiffeley Mill Road a short distance west.

The lock offers views of the Potomac. The towpath west of Seneca Creek passes a pond that can be good for waterbirds.