Mona and Monito Islands NNL, located in Puerto Rico, was designated on May 15, 1975. Pictured is a photograph from the original evaluation of a cave entrance at Cueva del Diamente, near Sardinera Beach on Mona Island.
NPS photo
The NNL program was established in 1962 with the first site designations occuring in 1964. Since that time, individual NNL sites have reached their Golden Anniversary, or 50 years, of landmark designation. The milestone is remarkable in that it recognizes 50 years of voluntary conservation, committment, and partnership with landowners and managers of these NNL sites.
In 2025 we recognize and celebrate the Golden Anniversary of 29 NNL sites. These NNLs were officially designated when then Secretary of the Interior, Stanley K. Hathaway, signed the designation memos on May 15, 1975.
