The Persian Gulf, in the Southwest Asian region, is an extension of the Gulf of Oman located between Iran (Persia) and the Arabian Peninsula. The natural environment of the Persian Gulf is very rich with good fishing grounds, extensive coral reefs, and abundant pearl oysters.
Geography
Satellite image showing the Persian Gulf, the Strait of Hormuz is the dramatic constriction on the right third. This inland sea of some 233,000 km˛ 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 Arvand rud, which carries the waters of the Euphrates and the Tigris. Its length is 989 kilometers, separating mainly Iran from Saudi Arabia with the shortest divide of about 56 kilometers in the Strait of Hormuz. The waters are overall very shallow and have a maximum depth of 90 meters and an average depth of 50 meters.
Countries with a coastline on the Persian Gulf are (clockwise, from the north): Iran, Oman (exclave of Musandam), United Arab Emirates, Saudi Arabia, Qatar on a peninsula off the Saudi coast, Bahrain on an island, Kuwait and Iraq in the northwest. Various small islands lie within the Persian Gulf.

Oil and gas
The Persian Gulf and its coastal areas are the world's largest single source of crude oil and related industries dominate the region. Al-Safaniya, the world's largest offshore oilfield, is located in the Persian Gulf. Large gas finds have also been made with Qatar and Iran sharing a giant field across the territorial median line (North Field in the Qatari sector; South Pars Field in the Iranian sector). Using this gas, Qatar has built up a substantial liquefied natural gas (LNG) and petrochemical industry.
The oil-rich countries (excluding Iraq) that have a coastline on the Persian Gulf are referred to as the Persian Gulf States. Iraq's egress to the Persian Gulf is narrow and easily blockaded consisting of the marshy river delta of Arvand rud/Shatt al-Arab, which carries the waters of the Euphrates and the Tigris Rivers, where the left (East) bank is held by Iran.

Etymology
The experts, who have worked on the name of Persian Gulf, became unanimous considering the name of Persian Gulf as the correct term. For at least during the past 2500 years, i.e. from the rise of Achaemenid dynasty (550-330 B.C.) there has never been seen such a consensus in the Middle East among writers and historians on one name during the past twenty-five centuries. The rise pf Achaemenid dynasty, and center of power which was from the province of Pars (Persis, or modern Fars) in the southwestern region of the Iranian plateau. Consequently in the Greek sources, the body of water that bordered this province came to be known as the Persian Gulf.
Considering the historical background of the name Persian Gulf, Sir Arnold Wilson mentions in a book, published in 1928 that:
“No water channel has been as significant as Persian Gulf to the geologists, archaeologists, geographers, merchants, politicians, excursionists, and scholars whether in past or in present. This water channel which separates the Iran Plateau from the Arabia Plate has enjoyed an Iranian Identity since at least 2200 years ago.”
” No written deed has remained since the era before the Persian Empire, but in the oral history and culture, the Iranians have called the southern waters: "Jam Sea", "Iran Sea", and “Pars Sea".
During the years: 550 to 330 B.C. coinciding with sovereignty of the first Persian Empire on the Middle East area, especially the whole part of Persian Gulf and some parts of the Arabian Peninsula, the name of "Pars Sea" has been widely written in the compiled texts.
In the travel account of Pythagoras, several chapters are related to description of his travels accompanied by Darius the Great, to Susa and Persepolis, and the area is described. From among the writings of others in the same period, there is the inscription and engraving of Darius the great, installed at junction of waters of Arabian Gulf (Ahmar Sea = Red sea) and Nile river and Rome river (current Mediterranean) which belongs to the 5th century BC where, Darius, the king of Achaemenid Empire has named the Persian Gulf Water Channel: Pars Sea.

Naming Dispute
A historical map is altered to erase the word "Persian" from the Persian Gulf in a Dubai museum, United Arab Emirates.
Since the 1960s with the rise of Arab nationalism (Pan-Arabism), starting with Jamal Abdul Nasser's Arab Republic of Egypt, some Arab countries, including the ones bordering the Persian Gulf, have adopted the term "Arabian Gulf" to refer to the waterway. This is controversial and not commonly used outside of the Arab world, nor is it recognized by the United Nations and other international organizations. The United Nations on many occasions has requested that only "Persian Gulf" be used as the official and standard geographical designation for the body of water."Arabian Gulf" is also an ancient name for the Red Sea. Hecataeus (472 to 509 B.C.) can be stated where Persian Gulf and Arabian Gulf (Red Sea) have been clearly shown. Also a map has remained from Herodotus, the great Greek historian (425-484 B.C.) which introduces Red Sea as the Arabian Gulf.
In the world map of Diseark (285-347 B.C.) too, Persian Gulf and Arabian Gulf have been clearly distinct. At the same time, many maps and deeds prepared up to the 8th century by the historians such as Arrian Hecataeus, Herodotus, Hiparek, Claudius Batlamious, Krats Malous,…… and in the Islamic period, Khw?rizm?, Abou Yousef Eshagh Kandi, Ibn Khordadbeh, Batani (Harrani), Mas'udi, Balkhi, Estakhri, Ibn Houghal, Aboureyhan Birouni and others, mention that there is a wide sea at south of Iran named “Pars Sea”, “Pars Gulf”, “Fars Sea”, “Fars Gulf”, “Bahre Fars”, “Sinus Persicus” and “Mare Persicum” and so on. In a book, named “Persilus Aryateria”, the Greek traveller of the 1st century A.D. has called the Red Sea as Arabian gulf; the Indian ocean has been named Aryateria Sea; the waters at Oman Coast is called Pars Sea; Barbarus region (between Oman and Yemen coast are called belonging to Pars, and the Gulf located at south side of Iran is named: “Persian Gulf”. By describing the water body, the life of Persians living at both sides have also been confirmed.
However, in Twenty-third session of United Nation in March-April 2006, the name of Persian Gulf is being confirmed as the legitimate and the official term to be used by members of United Nation.

Persian Gulf National Day
30 April has been named as Persian Gulf National Day in Iran.