11. Geography
Mona has an area of about 57 km2 (22 sq mi) and lies 66
km (41 mi) west of the main island of Puerto Rico, 61 km
(38 mi) east of the Dominican Republic, and 49 km (30
mi) southwest of Desecheo Island, another island in the
Mona Passage.
Mona has been designated an ecological reserve by the
Puerto Rican government and is not permanently
inhabited. The US census of 2000 reports six housing
units, but a population of zero.[7] The island is a ward
(barrio) of the municipality of Mayagüez, together with
Monito Island 5 km northwest (Isla de Mona e Islote
Monito barrio). This is the largest ward of Mayagüez by
area, and the only one without permanent population. The
total land area of both islands in the barrio is about 56.93
km² (Mona Island 56.783 km² and nearby Monito Island
0.147 km²), and it comprises 28.3 percent of the total land
area of the municipality of Mayagüez. Desecheo Island,
49 km to the northeast, is part of Sabanetas barrio.
12. Mona is a mainly flat plateau surrounded by sea
cliffs. It is composed of dolomite and limestone
with many caves found throughout. With an arid
climate and untouched by human development,
many endemic species inhabit the island, such as
the Mona Ground Iguana (Cyclura cornuta
stejnegeri). Its topography, ecology, and modern
history are similar to that of Navassa Island, a
small limestone island located in the Jamaica
Channel, between Jamaica and Haiti.
