Opal, SD

ZIP code 57765 serves Porcupine, on the Pine Ridge Indian Reservation in Oglala Lakota County, southwestern South Dakota. It is a sparsely settled community amid prairie, ravines, and prominent buttes. Local landmarks include Porcupine Butte and KILI Radio; Badlands National Park’s Stronghold Unit and the Wounded Knee historic site are major regional landmarks nearby.