The Chocolate Mountain Aerial Gunnery Range (CMAGR), is a 456,000 acre (1850 km²) Open-Area, approximately 20 miles wide, east to west, and 50 miles long, northwest to southeast, which is used by the Navy and Marines for aerial bombing and live fire aerial gunnery practice. It straddles the northern portion of the Chocolate Mountains to the east of the Salton Sea in Imperial and Riverside Counties, California, with restricted airspace in both California and Arizona.