Joshua Tree National Park is located in southeastern California. Declared a U.S. National Park in 1994. It is named for the Joshua tree (Yucca brevifolia) forests native to the park. It covers a land area of 319,598 ha. A large part of the park (173,890 ha) is designated to wilderness area. Straddling the San Bernardino County/Riverside County border, the park includes parts of two deserts, each an ecosystem whose characteristics are determined primarily by elevation: the higher Mojave Desert and lower Colorado Desert. The Little San Bernardino Mountains run through the southwest edge of the park.