Lerma (formally Lerma de Villada) is a city and municipality located just east of Toluca and 54 km west of Mexico City in Mexico State, Mexico. The city was founded in the early colonial period and named after the Duke of Lerma in Spain. The municipal area saw two battles of the Mexican War of Independence, the Battle of Monte de las Cruces and the Battle of Lerma. For a time after independence, the city was the capital of Mexico State before it was moved to Toluca. The municipality is in one of the most densely populated areas of Mexico and is growing. Much of this growth is occurring near the Toluca-Mexico City highway and on the floodplains of the Lerma River. The latter has caused significant problems with flooding when the river overflows its banks during the rainy season.
The Nahuatl name for the area is Cacamilhuacan, which translates to “crows in the field.” In the early colonial period, the area was called Santa Clara Cacamilhuacan. The municipality has both an Aztec glyph with a crow reflecting its Nahuatl name and a Spanish coat of arms.