The Presidio of San Francisco is a 1,491-acre national park site and is part of the Golden Gate National Recreation Area. The Presidio was in continuous use as a military post from 1776 to 1994, spanning the Spanish, Mexican, and United States periods. From March 28, 1776, when Spain's Lieutenant Colonel Juan Bautista de Anza arrived at the Golden Gate, until October 1, 1994, when the Sixth U.S. Army marched out the gate for the last time, the Presidio of San Francisco was a military post with local, regional, continental, and global connections. The original el Presidio was established by the Spanish as the northernmost outpost of colonial New Spain (Mexico). With Mission San Francisco de Asis (Mission Dolores), and the later pueblo at Yerba Buena Cove, these three early settlements marked the genesis of the City of San Francisco. Before the arrival of the Europeans, this northwestern corner of San Francisco was Ohlone territory for more than a thousand years. The Presidio in its entirety was declared a National Historic Landmark District for its importance to Spanish colonial settlement and its prominent U.S. Army history.