莱尔马河是墨西哥的河流，河道全长750公里，流域面积47,116平方公里，发源自该国中部高地，最终在瓜达拉哈拉附近注入查帕拉湖。

The Lerma River (Spanish:Río Lerma) is Mexico's second longest river. It is a 750 km-long (470 mi) river in west-central Mexico that begins in Mexican Plateau at an altitude over 3,000 metres (9,843 ft) above sea level, and ends where it empties into Lake Chapala, Mexico's largest lake, near Guadalajara, Jalisco. Lake Chapala is the starting point of Río Grande de Santiago, which some treat as a continuation of the Lerma River. In combination, the two are often called the Lerma Santiago River (Spanish:Río Lerma Santiago). The Lerma River is notorious for its pollution, but the water quality has demonstrated considerable improvement in recent years due mostly to government environmental programs and through massive upgrading projects of sanitation works.