[1][2] 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.

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.

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.

On or about October 22, the Americans reached a friendly Mohave village and learned from a Spanish speaking native that Fort Yuma and the mouth of the Gila River, which connects with the Colorado, was only eight days distant.

At the fort Sitgreaves discovered that the outpost was badly in need of provisions also and as a result, the party had to cook and eat all of their mules before making it to San Diego.