It is the largest peninsula in the world, at 3,237,500 km2 (1,250,000 sq mi). The Arabian Peninsula consists of the countries Yemen, Oman, Qatar, Bahrain, Kuwait, Saudi Arabia and the United Arab Emirates, and parts of Jordan and Iraq. The peninsula formed as a result of the rifting of the Red Sea between 56 and 23 million years ago, and is bordered by the Red Sea to the west and southwest, the Persian Gulf to the northeast, the Levant to the north and the Indian Ocean to the southeast. The Arabian Peninsula plays a critical geopolitical role in the Middle East and the Arab world due to its vast reserves of oil and natural gas.
Before the modern era, it was divided into four distinct regions: Hejaz (Tihamah), Najd (Al-Yamama), Southern Arabia (Hadhramaut) and Eastern Arabia. Hejaz and Najd make up most of Saudi Arabia. Southern Arabia consists of Yemen and some parts of Saudi Arabia (Najran, Jizan, Asir) and Oman (Dhofar). Eastern Arabia consists of the entire coastal strip of the Persian Gulf.
The Arabian Peninsula is located in the continent of Asia and bounded by (clockwise) the Persian Gulf on the northeast, the Strait of Hormuz and the Gulf of Oman on the east, the Arabian Sea on the southeast and south, the Gulf of Aden on the south, the Bab-el-Mandeb strait on the southwest and the Red Sea, which is located on the southwest and west. The northern portion of the peninsula merges with the Syrian Desert with no clear border line, although the northern boundary of the Arabian Peninsula is generally considered to be the northern borders of Saudi Arabia and Kuwait.
The most prominent feature of the peninsula is desert, but in the southwest there are mountain ranges, which receive greater rainfall than the rest of the Arabian Peninsula. Harrat ash Shaam is a large volcanic field that extends from the northwestern Arabian Peninsula into Jordan and southern Syria.
The peninsula's constituent countries are (clockwise north to south) Kuwait, Bahrain, Qatar, and the United Arab Emirates (UAE) on the east, Oman on the southeast, Yemen on the south and Saudi Arabia at the center. The island nation of Bahrain lies off the east coast of the peninsula.