A highly informative visitor center on a northern slope of the hills surrounding the broad San Pasqual Valley tells the story of the bloodiest California battle of the Mexican War. In the summer of 1846, Brig. Gen. Stephen W. Kearny and a detachment of the Army of the West set out toward Los Angeles from Fort Leavenworth, Kansas, to establish an American government in California. On the foggy morning of December 6, Kearny's troops, suffering from hunger and cold after the long journey, engaged a Mexican troop commanded by Andrés Pico on this site. Their rifles disabled by wet powder, the Americans found themselves at a disadvantage to the Californio lancers: 21 Americans and one Californio were killed. An observation area with explanatory diagrams overlooks the scene of the battle, while interpretive displays and a video (10min) relate the history of the area and of the Mexican War. Traversing the slopes surrounding the visitor center, a self-guided nature trail (.5mi) offers a good introduction to the plants of the chaparral community. A plaque .4mi west marks the site where the Americans camped the night after the battle. State Park volunteers conduct tours of the facility and stage living history programs October through June. The battle is re-created in December.