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.