The United States Congress designated the Joshua Tree Wilderness in 1976 and it now has a total of 594,502 acres. All of this wilderness is located in California and is managed by the National Park Service. The Joshua Tree Wilderness is bordered by the Sheephole Valley Wilderness to the north and the Pinto Mountains Wilderness to the north. The California Desert Protection Act of 1994 transformed Joshua Tree National Monument into a national park and expanded the old designated Wilderness by 133,382 acres. The additions thrust north into the Pinto Mountains, northeast into the Coxcomb Mountains, southeast into the Eagle Mountains, and southwest into the Little San Bernardino Mountains. Most of the park away from road corridors is wilderness, a fabulous meeting place of two desert ecosystems. The lower, drier Colorado Desert dominates the eastern half of the park, home to abundant creosote bushes, the spidery ocotillo, and the "jumping" cholla cactus. The slightly more cool and moist Mojave Desert covers the western half of the park, serving as a hospitable breeding ground for the undisciplined Joshua tree. You'll find examples of a third ecosystem within the park: five fan-palm oases, where surface or near-surface water gives life to the stately palms. By day, you might spy bighorn sheep on mountainous slopes, numerous lizards lazing in the heat, and eagles soaring in bright sunlight. Still, it's nighttime that truly brings the desert to life, with tarantulas, rattlesnakes, coyotes, jackrabbits, bobcats, kangaroo rats, and burrowing owls responding to the lure of the dry, cool air. You'll witness some of the most fascinating geologic displays to be found in any of Southern California's desertland: twisted rock formations and granite monoliths painted with faded colors into a giant and beautiful mosaic. These rocks are an immense attraction to rock climbers. You won't find a lot of trails, but you will find travel relatively easy in multitudes of arroyos and playas, bajadas, and narrow ravines that require scrambling over skin-scraping boulders. Carry water. Joshua Tree National Park is made up of 75 percent wilderness and lies 140 miles east of Los Angeles, 175 miles northeast of San Diego, and 215 miles southwest of Las Vegas. You can approach it from Interstate 10 and Hwy 62 (Twentynine Palms Highway). The closest airport is in Palm Springs. Public transportation to the park is not available. There are three park entrance stations: 1) The west entrance is located five miles south of the junction of Highway 62 and Park Boulevard at Joshua Tree Village. 2) The north entrance is in Twentynine Palms, three miles south of the junction of Highway 62 and Utah Trail. 3) The south entrance at Cottonwood Spring, which lies 25 miles east of Indio, can be approached from the east or west, also via Interstate 10.