District Solan came into existence on 1st September, 1972, its name from the local deity SHOOLINI.” Solan is considered as gateway to Himachal Pradesh which was carved out from the Solan and Arki Tehsils of the then “MAHASU” district and Tehsil Kandaghat and Nalagarh of the then Shimla district. Solan district has an area of 1936 sq.kms. The district has been divided in 4 administrative sub-divisions. It is known as the “Mushroom city of India” because of the vast mushroom farming in the area and the mushroom research centre situated at Chambaghat. Solan is also called the “City of Red Gold”, in reference to the bulk production of tomatoes in the area. The elevation of the district ranges from 300 to 3000 meters above mean sea level. The terrain is mostly mountainous except valleys of Saproon in Solan Tehsil, Doon in Nalagarh Tehsil and Kunihar in Arki Tehsil. The district is surrounded in the south by Punjab and Harayana State, from north by Shimla, on the western side by the Bilaspur district and eastern side by Sirmour district. It is located between latitude 76.42 degree and 72.20 degree east and latitude 30.65 degree and 31.15 degree north. This district is covered by catchment areas of four important rivers namely Satluj, Ashwani, Giri and Ghagher.