The Rose–Baley Party was the first European American emigrant wagon train to traverse the 35th parallel route known as Beale's Wagon Road, established by Edward Fitzgerald Beale, from Zuni Pueblo, New Mexico to the Colorado River near present-day Needles, California.
In 1858, a wealthy businessman from Keosauqua, Iowa, Leonard John Rose, formed the party after hearing stories from gold miners returning from California. He subsequently financed a well-equipped wagon train that included twenty horses and two hundred head of purebred red Durham cattle. He also acquired four large covered wagons and three yoke of oxen to pull them each wagon. The Rose company left Iowa in early April, and in mid-May they were joined by the Baley company, led by a forty-four-year-old veteran of the Black Hawk War, Gillum Baley. Their combined outfits numbered twenty wagons, forty men, fifty to sixty women and children, and nearly five hundred head of cattle. John Udell, a 62-year-old Baptist minister kept a daily journal of the party's travels, recording the locations of their campsites, documenting their progress, and noting the availability of resources.
On August 30, 1858, after having traveled more than 1,200 miles (1,900 km) in four months, the Rose–Baley Party were attacked by three hundred Mohave warriors as they prepared to cross the Colorado River. Eight members of the party were killed, including five children, and thirteen wounded. The emigrants held off the assault, killing seventeen Mohave, but decided to backtrack more than 500 miles (800 km) to Albuquerque, New Mexico, instead of continuing on to their intended destination in southern California.