La Quinta is located at 33°40′31″N 116°17′51″W (33.675373, −116.297391). According to the United States Census Bureau, the city has a total area of 35.6 square miles (92 km2), of which, 35.1 square miles (91 km2) of it is land and 0.4 square miles (1.0 km2) of it (1.22%) is water. The city’s elevation is 56 feet (20 m) above sea level.
La Quinta is located on the floor of the Coachella Valley, and is surrounded almost entirely by the Santa Rosa Mountains. As the floor of the valley sank, it was covered by the Pacific Ocean. Silt deposits from the flow of the Colorado River into the Gulf of California caused the basin to be cut off from the ocean.
Five hundred years ago, the Colorado River changed its course and the east Coachella Valley flooded, leading to the creation of Lake Cahuilla, which is fresh water.