It evolved through the use of local natural materials, the unique regional conditions of the Southwest and the influence of Indian and Spanish cultures.
Indian cultures traces their roots back a millennium before the arrival of the Spanish explorers.
Architecture at Chaco Canyon and Mesa Verde, some of the oldest and largest Anasazi villages, show the use stone masonry and pine timbers. Later Puebloan dwellings use adobe walls with their rounded edges. The Spanish brought with them the town planning style of central main plazas and mission style of churches. By the turn of the century regional influences could be seen in the Southwest's architecture. Elizabeth Hughes and Helen Hunt Jackson were instrumental in saving and preserving many of California's early missions.