The Sitgreaves Expedition Down the Zuni and Colorado Rivers in 1851 was a combined American scientific and military mission to explore the Zuni River, the Little Colorado River and the Colorado River in 1851. Setting out from northern New Mexico, the expedition traveled west across Arizona and then south along the Colorado to Fort Yuma in California. Mohave native Americans attacked the explorers during their trek across the desert and in a short battle the natives were repulsed. Expedition Since the Mexican Cession of 1848, topographers, naturalists and other enthusiasts had wanted to explore two of the largest rivers in the newly acquired lands so in 1850, an expedition was organized for that purpose. United States Army commanders were also interested in the area as tension with the Mormons was high and war was expected. Specifically the expedition was sent to map the riverways and determine if they could be navigated by river steamers. Before the establishment of railroads across the Old West, the frontier's riverways were seen, and used, as a valued means of transportation. Captain Lorenzo Sitgreaves, of the Corps of Topographical Engineers, was appointed commander and with fifty infantrymen, some porters and the small group of enthusiasts, they headed west from the Zuni Pueblo in September 1851 for the Zuni River. Passing through the Petrified Forest, the party reached the Zuni and followed it southwest to its mouth at the confluence with the Little Colorado just north of present-day Woodruff, Arizona. At the Little Colorado the Americans proceeded northwest until having to detour around a canyon in which the river flowed through. It was during this detour that the Americans discovered the Wupatki Ruins before making a prolonged turn around the south side of the Bill Williams Mountain. When they reached what was later named Union Pass, near Bullhead City, the party found the Colorado. The expedition up to this point was pleasant, the topographers made their maps, the artists drew several pictures of fauna and landscapes and the military men focused on keeping the enthusiasts from staying at one place for too long. After making it only a short distance south down the Colorado, Captain Sitgreaves' men reported signs of natives in the area and soon after they were met by the Mohave at their camp. Initially peaceful, the Mohaves invited the Americans to a pow wow where the two groups exchanged gifts and engaged in