The Fort Polk Joint Readiness Training Center is not suitable for big rigs. To get to the RV dump station, go north on US 171 from Ft. Polk until you reach Anacoco. Then, turn left onto LA 111 and continue for 4.8 miles. You will pass Toledo Bend State Park. Look for the sign on the left at Army Recreation Road. The RV dump station is located 45 minutes away from Ft. Polk.
