El Camino Real (Spanish for The Royal Road, also known as The King's Highway), sometimes associated with Calle Real, usually refers to the historic 600-mile (966-kilometer) road connecting the former Alta California's 21 missions (along with a number of sub-missions), four presidios, and three pueblos, stretching from Mission San Diego de Alcalá in San Diego in the south to Mission San Francisco Solano in Sonoma north.