Misión San Miguel Arcángel de la Frontera

Mission San Miguel Arcángel de la Frontera was founded by the Dominican friar Luis Sales on 28 March 1787, halfway between San Vicente Ferrer and San Diego, to convert the Kumeyaay. The first site, El Encino, lost its spring, so in 1788 the mission moved about 11 km west to a spot a little over 2 km from the sea that Fray Juan Crespí had named San Juan Bautista. That is today's La Misión valley, and the ruins are there.

Near here in 1773, Fray Francisco Palóu had a large cross raised to mark the line between the Franciscan missions to the north and the Dominican ones to the south; in 1804 the same line split Alta from Baja California. By the end of 1787 the mission counted 137 converts, it peaked at some 350 to 400 in 1824, and by 1830 only 78 were left. At its height it ran over 3,000 cattle, goats and sheep and 400 horses and mules and grew wheat, maize, beans, lentils, barley and grapes, the start of the vaquero ranching culture of the northern peninsula. Around 1810, after floods washed out its fields, Fray Tomás de Ahumada moved part of the work north to El Descanso. No mission activity is recorded after 1834, and in 1862 the Crosthwaite family bought the land for their ranch, La Misión Vieja de San Miguel.

The compound was a rectangle with the church and living quarters on the east and south sides, an open patio, a single gate at the southeast corner guarded by a barracks, four granaries and an irrigation ditch. Walls were adobe, 0.9 to 1.1 m thick, on round-stone footings. Three fragments of wall survive. Under its Camino Real Misionero de las Californias program, INAH coats them in a sacrificial layer of clay, sand, nopal and manure, and has consolidated the foundations and braced one wall.