The Sierra Pinta or Sierra Pintas are a narrow remote block faulted northwest-southeast trending mountain range, about 22 miles (35 km) long located in southwestern Arizona in the arid northwestern Sonoran Desert, just north of the Pinacate Reserve of northern Sonora, Mexico. The mountains derive their name from the contrast of different colored rocks, with the northern end of the range mostly light granite, the southern end mostly dark gneiss, and a dramatic dividing line where two meet.