Peteroa is a small town west southwest of the town of Sagrada Familia, Chile.
Peteroa is also the name of the location of the fortress built by Lautaro and the site of the Battle of Peteroa. This location is uncertain and sometimes confused with the place on the Mataquito River where Lautaro was killed during the Battle of Mataquito in 1557. His fortress of Peteroa built in 1556 was located near Teno "twenty leagues from the city of Santiago". A soldier in this campaign under Juan Godíñez, Alonso Lopez de la Raigada refers to the 1556 fortress as "Peteroa" and the camp where Lautaro was killed as "Mataquito" and also refers to "Peteroa y Mataquito" as separate places. Pedro Mariño de Lobera does not give a place name to the location of the 1556 fortress. He does call the place of the 1557 battle he took part in as being at the "lugar de Mataquito". The contemporary chronicler Alonso de Góngora Marmolejo gives no place names to either location in his account.
Peteroa is named as the location of the confluence of the rivers Teno, Pumaiten, and Lontué to form the Mataquito River in the eighteenth century description of the province of Maule. The current town of Peteroa may be the vicinity where this fortress was located on the south bank of the Mataquito river and his second camp was located across the Mataquito river on its north bank.