Travelers are voting Crystal Lake Amphitheater as the best ruin in Ontario. There are 1 ruin in La Canada Flintridge a city just 68 km from Ontario and 1 ruin in San Juan Capistrano which is 92 km distant. The most popular of these are Crystal Lake Amphitheater in La Canada Flintridge and Mission San Juan Capistrano in San Juan Capistrano. You can find 5 ruins in California and 37 ruins in the country of United States. Our members favorite in California is Ryan House and Lost Horse Well and Chaco Culture National Historical Park is the top pick in United States. Want more? Check out our map of ruins in Ontario.