 Irvine Regional Park, created in 1897, now occupies much of the lowermost Santiago Creek Canyon, between Santiago Creek Dam and Villa Park Reservoir.The park was created officially on October 5 of that year as "Orange County Park", and originally it consisted of of woodland along the riparian course of Santiago Creek.At first, Santiago Creek flowed freely through the park, but with the completion of Santiago Dam in 1931, that was no longer possible.