The terrain of Navassa Island consists mostly of exposed coral and limestone, the island being ringed by vertical white cliffs nine to 15 meters high, but with enough grassland to support goat herds. There are also dense stands of fig-like trees and scattered cactus on the island. Its topography and ecology is similar to that of Mona Island, a small limestone island located in the Mona Passage, between Puerto Rico and the Dominican Republic. It shares the same historical similarities as Mona Island since both are U.S. territories, were once centers of guano mining, and presently are nature reserves. Transient Haitian fishermen and others camp on the island but the island is otherwise uninhabited. It has no ports or harbors, only offshore anchorages, and its only natural resource is guano; economic activity consists of subsistence fishing and commercial trawling activities.
