The works and texts of many Muslim geographers remain in the knowledge of the geography of the Islamic countries, including those located in the territory of Islam. Among these works, we can mention the "Masalak and the Mallak" by Ibrahim bin Muhammad, Abu Ishaq Karkhi Estakhri (346 q.), Who is one of the first Iranian geographers of the Muslim world in the 4th century AH in Iran. This work, translated byan obscure writer in the fifth century AH, refers to the position of the Persian Gulf. In many geographical resources related to the Islamic regions, the Persian Gulf and its importance is named the Persian Gulf, Pars Sea and... These texts, in addition to geographic value, are historically, politically, military, economic, social, cultural, etc. of great importance. And should be seriously investigated in order to maximize theirvalue. "Masalak and the countries" is one of the early texts of the fourth century AH Which is essential for the geographical study of many regions of Iran in that epoch In this research, this Iranian Sea has been studied with the aim of understanding the historical geography of the Persian Gulf at that time.