I wasn't looking for Mullan Road historylink.org but happened upon it while taking in the change from the Palouse River valley to Washtucna Coulee. Mullan Road in Adams County just happens to be located at the location where the Palouse River Valley turns into Washtucna Coulee.
Mullan Road heading north from State Highway 26.
Mullan Road is named for John Mullan, the army officer that surveyed it and oversaw its construction. The road was surveyed and built between 1855 and 1862 and was constructed as an army road from Fort Benton in present day Montana to Fort Walla Walla. John Mullan managed to pull of some of this work during the Yakima Indian War. In fact he had begun surveys prior to the fighting, but his work was put on hold until after the gruesome battles at Spokane Plains and Four Lakes. Mullan maintained very good relations with the tribes and utilized their knowledge for routing the road.
The road followed very ancient trails with deviations for meeting grade requirements for wagon travel. Interstate 90 follows the Mullan's route through the mountains of northern Idaho across Mullan Pass. For the dry lands of eastern Washington, Mullan also needed to consider water sources to water stock and horses and locations where feed could be obtained for the animals.
Mullan Road south of Highway 26 has been long out of use but was used recently enough that its trace can still be seen heading across the upper most reach of Washtucna Coulee.
Trace of Mullan Road south of Highway 26
The notch in the valley wall is where the Palouse River turns south
It is too bad that the US Government surplussed the Mullan Road long ago. Its trace leads to the spot where the Palouse River exits its old valley and enters a narrow canyon at Upper Palouse Falls. No access without permission across private land.
I didn't take Mullan Road north as my purposes required me to head north a bit more to the east, but I came across this faded commemorative sign along Cow Creek not far from Benge where the old Mullan Road entered the coulee occupied by Cow Creek. I realized that my travels on State and County roads from Walla Walla to Benge had been more or less been following Mullan's route through this landscape. A route that had long before been used by local people that have occupied this land for over 10,000 years.