Torre de Don Borja, Gothic fortified tower in Plaza Mayor, Santillana del Mar, Spain

The Torre de Don Borja is a square-plan tower of three storeys with a four-sided pitched roof, standing on the old market square of Santillana del Mar's historic centre. Part of its ground floor facing the square forms a portico entered through a pointed arch. The facade carries two Gothic shields with the arms of the Barreda family, sheltered by projecting stones. It is joined to another building by a 16th-century courtyard.

The present building dates from the 15th century, though its origin is probably medieval; it was never documented as a defensive structure. Its name comes from Borja Barreda, who held the entail in 1844. It later belonged to the Barreda and Güell families, then to Infanta María de la Paz de Borbón, a gift from Juan Antonio Güell y López, and afterwards to Princess María de las Mercedes de Baviera y Borbón. Restored in 1981 as the seat of the Fundación Santillana, it was acquired in 2018 by heirs of Jesús Polanco and reopened in summer 2019.

The Barreda family marked the tower with two Gothic shields on its facade, which remain visible today. These symbols show the building's connection to a powerful local family from centuries past.

The tower sits in the village center and is easy to reach on foot, with the surrounding area typically paved and accessible to walkers. Visitors can explore the interior or participate in exhibitions and guided tours offered regularly.

The tower has carried several nicknames over the centuries: Torre de Don Borja-Bracho, La Torrona and Torre de la Infanta. The last recalls Infanta María de la Paz de Borbón, who received it as a gift from Juan Antonio Güell y López, count of Güell and marquis of Comillas.