Located in the state of California (USA).
Joshua Tree National Park is an American national park in southeastern California, east of Los Angeles, near Palm Springs. The park is named for the Joshua trees (Yucca brevifolia) native to the Mojave Desert. Originally declared a national monument in 1936, Joshua Tree was redesignated as a national park in 1994 when the U.S. Congress passed the California Desert Protection Act. Encompassing a total of 790,636 acres (1,235.37 sq mi; 3,199.59 km2)—an area slightly larger than the state of Rhode Island—the park includes 429,690 acres (671.39 sq mi; 1,738.89 km2) of designated wilderness. Straddling the border between San Bernardino County and Riverside County, the park includes parts of two deserts, each an ecosystem whose characteristics are determined primarily by elevation: the higher Mojave Desert and the lower Colorado Desert. The Little San Bernardino Mountains traverse the southwest edge of the park.
Source: Wikipedia