Oman, also known as the Sultanate of Oman, is an absolute Islamic monarchy located on the southeast coast of the Arabian Peninsula in southwest Asia. It is bordered to the northwest by the UAE; Saudi Arabia to the west; and Yemen to the southwest. Oman's coast abuts the Arabian Sea to the south and east and the Gulf of Oman to the northeast. Since 1990, Oman has been a member of the Gulf States Union.