After five years the Mission moved to a location several miles upriver at the present site of Mission San Diego de Alcalá. Presidio Hill remained the primary settlement for several decades because it was defensible against attack by European enemies or hostile Native Americans. As the need for defense decreased, settlers preferred to live at the base of the hill because of greater convenience. In the 1820s the town of San Diego grew up at the base of the bluff, at the site commemorated by Old Town San Diego State Historic Park. The Presidio was abandoned and fell into disrepair.