The 624 mile long Mullan Road connected Walla Walla to Fort Benton on the Missouri River. Constructed as a military road by Lieutenant Mullan in the years 1859 to 1862, the road incorporated stretches of corduroy road and numerous bridges. Military supply wagons and miners frequented the road, however the road soon fell into disrepair, being described in its later years as a mere trail.
Modern highways have been constructed over parts of the Mullan Road. However, some modern "pioneers" still ride and drive wagons over sections of the road where its faint presence can still be followed through the Channeled Scablands of Eastern Washington.