Fuerte Castamata, Military fort and museum in Matamoros, Mexico.

Fuerte Casamata is a 19th-century fort in Matamoros whose name comes from the Latin casa armata, meaning 'armed house'. It was built as a military storehouse for ammunition, weapons and other supplies, and today houses the Museo Casamata, founded in 1970 by city chronicler Eliseo Paredes Manzano. The museum also holds the Archivo Histórico de Matamoros and a temporary exhibition room.

The fort was built in 1845 under General Manuel Rodríguez de Cela to defend the Mexican border. It was constructed during a period when Mexico needed to protect its territory after gaining independence.

The fort displays the role of military life in shaping Matamoros through exhibits of weapons and personal soldier items on view. These objects tell stories about daily routines and the people who served at this location.

The fort stands in Matamoros, Tamaulipas, near the Rio Grande and the Texas border. The building served as a munitions and weapons depot, and since 1970 it has housed the Museo Casamata, founded by city chronicler Eliseo Paredes Manzano. In 2006 the roof was restored and doors and windows were replaced, so the rooms are enclosed.

It is the last remaining fort from a network of defensive structures that once stretched across the Mexican border. Its survival reminds visitors of a whole system of fortifications that mostly disappeared over time.