In the spring of 1853, Congress authorized a US Army expedition made up of engineers and explorers and led by Isaac Ingalls Stevens, to survey a route from the Missouri River to the Columbia River suitable for building a railroad. Stevens assumed the task, but also kept in mind that the route should be suitable for a wagon road.
A small, dark-haired young man, Lieutenant John Mullan just out of West Point, was placed in charge of surveying, and later improving, a wagon route (now commonly called the Mullan Road) between Fort Benton (Montana) and Fort Walla Walla (Washington). Lieutenant Mullan commanded a workforce of more than 200, including civilian workers, soldiers, engineers, and surveyors who carved a 25-foot wide road across the region.
Although the road was never heavily used by the military, it was an important conduit for civilian passage, which hastened settling of the northwestern United States. In the first year after completion, it was used by an estimated 20,000 people, 6,000 horses and mules, 5,000 cattle and 83 wagons. The Mullan Road helped Walla Walla become the largest town in Washington Territory by 1870, with a population of 1,394. The road continued to serve as an important route until the completion of the Northern Pacific Railroad in 1883 provided faster and more convenient access to the region.
In 1836 Marcus Whitman a physician and missionary in the Oregon Country, along with his wife Narcissa started a mission Waiilatpu (Why-ee-lat-poo, the 't' is half silent), which means "place of the rye grass" in the Cayuse language also known as the Whitman Mission. The mission was located 6 miles from current day Walla Walla Washington, just west of the northern end of the Blue Mountains. Whitman would later lead the first large party of wagon trains along the Oregon Trail, establishing it as a viable route for the thousands of emigrants who used the trail in the following
The settlement was in the territory of both the Cayuse and the Nez Percé tribes of Native Americans. Marcus farmed and provided medical care, while Narcissa set up a school for the Native American children.
The influx of white settlers in the territory brought new diseases to the Indian tribes, including a severe epidemic of measles in 1847. In what became known as the Whitman Massacre, Cayuse tribal members murdered the Whitman’s in their home on November 29, 1847. Most of the buildings at Waiilatpu were destroyed. Twelve other white settlers in the community were also killed. For one month 53 women and children were held captive before negotiations led to them being released. In 1850, the tribe handed over five members to be tried for the murder of the Whitman’s. All five Cayuse were convicted by a military commission and hanged on 3 June 1850. The hanging was conducted by U.S. Marshal Joseph L. Meek. This event triggered an ongoing conflict between white settlers and local tribes, known as the Cayuse War an armed conflict that lasted from 1848 to 1855. This was the first of several wars between the original inhabitants and Euro-American settlers in that region that would lead to the placement of many of the Native Americans onto Indian reservations.