About 4.5 miles inland from central Oceanside, this was the largest California mission and the most successful in recruiting Native American converts. At one point some 3000 neophytes lived and worked here. After the Mexican government secularized the missions, San Luis fell into ruin; the adobe walls of the church, from 1811, are the only original parts left. Inside are displays on work and life in the mission, with some original religious art and artifacts.