In 1601 Alonso de Ribera built Fort Talcahuano to defend remaining Spanish settlements near Concepción and Fort Lonquén on the Lonquén River to secure estancias that provided food to the army.
On the coast Ribera sent captain Francisco Hernández Ortiz to establish a fort Valdivia on the site of the ruined city but it had to be abandoned by the starving remnant of its garrison after a terrible two-year siege.
The refugees from the abandoned city of Osorno under captain Francisco Hernández founded Fort Calbuco on a channel between the Reloncaví Sound and the Gulf of Ancud.
In 1621, Cristóbal de la Cerda y Sotomayor rebuilt the fort of Yumbel the same year it was destroyed.
In 1647, Martín de Mujica y Buitrón as a result of the Parliament of Quilín (1647) was able to reestablish forts at Valdivia, Santa Juana in 1648, and at Boroa in 1649.
In 1657 Pedro Porter Casanate restored the city of San Bartolomé de Chillán following its destruction at the beginning of the Mapuche Insurrection of 1655.
Meanwhile, captain Alonso de Cordova y Figueroa built Fort Tolpán at the confluence of the Renaico and Vergara Rivers.
In 1788 Governor Ambrosio O'Higgins built Fort Príncipe Carlos on the Duqueco River.
In 1792 the forces of Governor Ambrosio O'Higgins under Tomás de Figueroa took possession of the site of the city of Osorno ruined in 1602, and constructed a fort there.