|This stone plaque declares that in 1982 PRC declared Yu Yuan as a national protected monument.
For those of you who like trivia, the last character 立 li4 means officially "established" or "erected" when it follows the name of a government agency which has put up a sign. It comes from 立碑 li4bei1 to erect a monument.
Below is the aerial view from Wiki Maps. You can click on it to open a new window to take you to the map.