lake, west-central Mexico. It lies on the Mexican Plateau at 6,000 feet (1,800 metres) above sea level in the states of Jalisco and Michoacán. Chapala is Mexico's largest lake, measuring approximately 48 miles (77 km) east-west by 10 miles (16 km) north-south and covering an area of 417 square miles (1,080 square km). Despite its size, the lake is very shallow and is susceptible to infestations of water hyacinth. It is fed principally by the Lerma River from the east and is drained by the Río Grande de Santiago, which flows out of its northeastern side. The scenic setting, pleasant climate, picturesque villages dotting the shores, and good fishing make the lake a popular resort and, increasingly by the late 20th century, a retirement centre for U.S. citizens. Lying 30 miles (48 km) south-southeast of Guadalajara, it is easily accessible by highway, railroad, or air.