San Buenaventura Mission is the ninth Franciscan mission founded in California, and the last by Father Junípero Serra. The site was chosen within the limits of the present Ventura, Ventura County, near the beach and adjoining one of the native villages, and the usual founding ceremonies took place Mar. 31, 1782. The natives seemed pleased with the prospect and readily aided in the construction of the new buildings. The increase in the number of neophytes was not so rapid as at some of the missions. In 1790 there were 385; in 1800, 715; in 1810, 1,297; while the highest number, 1,328, was reached in 1816. In other respects the mission was very successful; it had more cattle (10,013 head) and raised more grain (9,400 bushels) in 1800 than any other place in California. Vancouver visited the mission in Nov. 1793, and remarked on the quantity, variety, and general excellence of its vegetables and fruits. The buildings also were excellent, though the new stone church was not completed and dedicated until 1809. During the first decade of the 19th century the mission continued the most prosperous in California. In 1810 there were 21,221 cattle, 3,276 horses and mules, and 8,543 small stock, with an average crop for the decade of 6,400 bushels. Though losing some what by 1820, the mission still retained first place. The earthquake of 1812, which destroyed the church at San Juan Capistrano, also severely injured the new church of San Buenaventura, and it was feared that the whole mission site was settling into the sea, so that all the inhabitants removed to higher ground for three months. After 1820 the mission declined rapidly, both in converts and in material prosperity.
In 1830 there were 726 neophytes, and 626 in 1834. Up to that time the total number of natives baptized was 3,805, of whom 1,909 were children, Secularization does not seem to have been carried out here until 1837. Bancroft estimates that in 1840 there were about 250 Indians in the community and as many more scattered in the district. In 1844 the mission was reported as still fairly prosperous; in 1846 the lands were sold for $12,000. The buildings remained in the possession of the Catholic Church, and since 1843 the mission has been the regular parish church of Ventura, which in garbled form was named from the mission. In 1893 the old church was so renovated as to lose much of its historic interest.
The Indians among whom San Buenaventura mission was established belonged to the Chumashan linguistic family, which probably furnished the major portion of the neophytes.