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 naming the "Arabian Gulf as the Persian Gulf" is that the Red Sea was named Arabian Gulf back then, which "prevented the Arabian Gulf from being named as Arabian Gulf, and instead the name Persian Gulf became common". According to a book "Documents on the Persian Gulf's name" (pp 92–98), the United Nations Secretariat and its specialized agencies have requested its staff to use only "Persian Gulf" as a standard geographical designation. The United Nations Group of Experts on Geographical Names discussed the naming issue during its 23rd session, held in Vienna from 28 March to 4 April 2006. According