Armero, or Armero-Guayabal, is a municipality in the Tolima Department, Colombia. According to the National Department of Statistics of Colombia, 12,852 lived in the town in 2005. Its median temperature is 26 °C. It was founded in 1895, but was not officially recognized as the seat of the region until 29 September 1908, by President Rafael Reyes. The town was originally named San Lorenzo. In 1930, the name was changed to Armero in memory of José León Armero, a national martyr.