Here the Potomac River makes a meandering four-mile loop around Prather’s Neck. To avoid the bend in the river, the canal engineers cut the canal one-half mile across the neck. Because of the rapid elevation change, these four locks were . . . — — Map (db m15285) HM
“Here at Four Locks mule barn, mules rested during the winter months. Boat captains left their mules here, paying a mule tended to care for them. Often the mules grew thin because the keeper did not feed the mules as well as their owners . . . — — Map (db m15278) HM