The park was established in 1971 to preserve 241,904 acres ( 377.98 sq mi ; 97,895.08 ha ; 978.95 km ) of desert landscape .
Is open all year with May through September being the highest visitation months .
The park was established in 1971 to preserve 241,904 acres ( 377.98 sq mi ; 97,895.08 ha ; 978.95 km ) of desert landscape and is open all year with May through September being the highest visitation months .