When dry, Racetrack surface is covered with small but firm hexagonal mud crack saucers that are typically 3 to 4 inches (7.5 to 10 cm) in diameter and about an inch (2.5 cm) thick. Death Valley National Monument Est. February 11, 1933. Est. as Death Valley National Park in 1994; 5,270 square miles (13,649 km2). Inyo County, CA.