Cárdenas is a municipality and city in the Mexican state of San Luis Potosí.

San Luis Potosí is a state in North Central Mexico that is divided into 58 municipalities. According to the 2020 Mexican census, it is the 19th most populated of Mexico's 31 states, with 2,822,255 inhabitants and the 15th largest by land area spanning 61,138.0 square kilometres (23,605.5 sq mi). The largest municipality by population is the city of San Luis Potosí, with 911,908 residents, while the smallest is Armadillo with 4,013 residents. The largest municipality by land area is Santo Domingo which spans 4,322.60 km2 (1,669.0 sq mi), and the smallest is Huehuetlán with 71.50 km2 (27.61 sq mi). The newest municipalities are El Naranjo, created out of Ciudad del Maíz, and Matlapa, carved from Tamazunchale, both established in 1994.