Chalus (Chaloos) is within the limits of the Caspian Sea to the north and to Tehran in the south, with suitable geographical conditions. Its main city is Chaloos, which is situated in the form of a crossroad and accounts for one of the ancient cities of the province and located in the central coastal plains of the Caspian Sea.
In the ancient times this city was called Saloos or Shahloos. Near this city were two other smaller cities by the names of Kabeereh and Kacheh. An historian writes that the ancient geographical scholars state that Chaloos was a part of Tabarestan. Mohammad Ebne Ovais, one of the commanders of the Arab caliphates, appointed his son Ahmad as ruler of Chaloos. During the invasion of Amir Teimoor, the city was turned to rubble and for centuries remained a tiny village.
At the beginning of 14th century AH., with government support it gradually developed, turning into a city. Today it is a beautiful city with a wide range of facilities for tourists.