San Carlos Fortress, Star fort and museum in Perote, Mexico.

San Carlos Fortress is an 18th-century military building in Perote, Veracruz. Its long, low wall of stone and adobe, mottled tan and grey, runs horizontally and ends at a central arched gateway topped by a rounded pediment with a small coat of arms. Small rectangular vents are spaced along the wall on both sides of the gateway, and a broad, slightly raised paved causeway with stone borders leads straight to the arch.

Spanish colonial authorities ordered construction in the early 1770s, with the fortress completed in 1776 to secure coastal trade routes. This period marked Spain's effort to strengthen military control across its Mexican territories.

The fortress's name comes from San Carlos, and its gate statues wear the uniform of late-18th-century Spanish infantry, a detail explained only by oral tradition. The site is remembered as the Perote Prison, where Texan prisoners from the Santa Fe and Mier expeditions were held between 1841 and 1844. Mexico's first military college opened here on 11 October 1823.

The fortress stands on open ground north of the Cofre de Perote, reached from Perote by the road toward the coast; the paved causeway leads straight to the arched gateway. The site was opened to the public after the state prison closed in March 2007, and the sources record no regular maintenance by the government, so surfaces may be overgrown.

During World War II, the fortress served as a detention camp for German and Italian nationals after Mexico joined the Allied forces. This lesser-known role demonstrates how the structure adapted to different purposes across the centuries.