Persian Gulf flooding of the basin started 15,000 years ago due to rising sea levels of the Holocene glacial retreat. This inland sea of some is connected to the Gulf of Oman in the east by the Strait of Hormuz; and its western end is marked by the major river delta of the Shatt al-Arab, which carries the waters of the Euphrates and the Tigris. In Iran this is called "Arvand Rood", where "Rood" means "river". Its length is , with Iran covering most of the northern coast and Saudi Arabia most of the southern coast. The Persian Gulf is about wide
Persian Gulf naming dispute "Persian Gulf" as the "Conventional" name, along with 14 "Variant" names in different languages, such as "Gulf of Iran", "Gulf of Ajam", "Gulf of Basra", "Arabian Gulf", "Persian-Arabian Gulf", "Gulf of Fars", and "Farsi Gulf". In "Persian Gulf States Country Studies" published in 1993 by the Federal Research Division of the U.S. Library of Congress, the authors follow the practise of the BGN by using "Persian Gulf" while acknowledging that the governments of Kuwait, Qatar, United Arab Emirates, Oman and Bahrain "officially reject the use of the term Persian Gulf—as do other Arab governments—and refer to that body of water