At 80 surface acres(on non-drought years) with a depth that averages 9 feet, Stoneman Lake is one of the only two Arizona lakes that are not manmade (Mormon Lake is the other). Most think the waterway was created in a volcanic crater; others theorize it occupies a collapsed sinkhole.
The waterway was name in honor of General George Stoneman, who is often remembered for his nearly fatal attempt at hauling supplies down the Gila River. After a meteoric charge of the Military Department of California-a command that included the Arizona Territory. -G.J Sagi, from the essential travel handbook Fishing Arizona