Château de Latsaga, Medieval castle in Ostabat-Asme, France

Château de Latsaga is a castle in the Bidouze plain at Ostabat-Asme, built from a 13th-century fortified house. Its walls of limestone ashlar are 1.45 m thick at the base and pierced by arrow slits, day slits, mullioned windows and window seats. A square tower with a pointed-arch doorway and a small round-topped opening stands in the complex.

The castle was built in the second half of the 14th century by extending a 13th-century fortified house for Pes de Laxague. It had no strategic role, as its site in the Bidouze plain offered no defensive advantage. Pes died there in 1393, and the castle passed to his nephew Bertran de Santa-Gracia. It later became a royal property and by the 19th century was an agricultural estate.

The castle is one of only two in the Basque Country built on the Gascon model, alongside the Château de Gixune. Its most noted Gascon feature is the stone floor of the entrance tower, placed in a corner rather than mid-wall, with slots for raising and lowering a portcullis. The Laxague family sold it in 1870 to a notary from Saint-Palais, M. Schilt, who passed it to M. Primorena of Izura; it has stayed in Izura hands since.

The castle is private property, now run as an equestrian farm, so access to the buildings is not open to visitors. It stands about a kilometre south-west of the village of Izura, next to the cemetery, in the Bidouze plain. The facades and roofs have been inscribed as a monument historique since 1 February 1988.

The castle stands in the Bidouze plain at a spot called Latsaga, meaning "place of watercourses". This flat site gave it no strategic value, so its construction is thought to reflect the kings of Navarre's wish for a loyal vassal in a region troubled by the Luxe and Gramont feuds until the 1385 peace.