Mauritania Business Directory: MRT is the ISO 3 alphabet country code of Mauritania. Currency of Mauritania is UM, which has a short code of MRO. Capital of Mauritania is Nouakchott. Mauritania has the population of 4540068 and approximate area is 1030700.00 square kilometers (or approx. 640476.98 square miles). Population density of Mauritania is approx. 4/Km2 (or approx. 2.4856/mile2)