The Battle of San Buenaventura was a battle fought on March 27 and March 28, 1838, between forces representing competing claims to the governorship of California, then a Mexican territory. The opposing forces consisted of supporters of Juan Bautista Alvarado based in Northern California and supporters of Carlos Antonio Carrillo from Southern California. The major action consisted of a cannon siege on the Carrillo loyalists who were encamped at the Mission San Buenaventura in Ventura, California. The Alvarado forces won the battle, as the Carrillo forces fled from the Mission under cover of darkness following the first day of the battle. Most of the Carillo forces were captured the following day at Saticoy, California. One person was killed in the battle, an Alvarado loyalist who was shot b