Muscat is located in northeast Oman. The Tropic of Cancer passes south of the area. It is bordered to its west by the plains of the Al Batinah Region and to its east by Ash Sharqiyah Region. The interior plains of Ad Dakhiliyah Region border Muscat to the south, while the Gulf of Oman forms the northern and western periphery of the city. The water along the coast of Muscat runs deep, forming two natural harbours, in Muttrah and Muscat. The Central Hajar Mountains run through the northern coastline of the city.