The geography of this Khun Song Forest is primarily a plain area with undulating slopes, which is classified as an expansive low plain. There is a high mountain range that runs north to south. On the eastern side, there is a parallel mountain extending to Khao Soi Dao Wildlife Sanctuary. The highest peak is Khao Sip Ha Chan, at 802 meters above sea level. There are low mountains, Khao Satorn, in the middle of the area, and Khao Saba in the south. The northern side connects to the same forest as Khao Ang Rue Nai Wildlife Sanctuary. Throughout this forest, there are many canals. The canal that is like a large artery is Khlong Tanot, which vast and deep. It has a certain width of almost the entire area, from the north to the west, with a large amount of water. On the northern side, there is Sai Canal. Additionally, there are other streams which originated from Khlong Tanot, including Dinso, Sai Canal, Khot Canal, Ikek Canal, Nam Pen Canal, Saba Canal, and Yang Canal. 

   The northeast and southwest monsoons effect the overall climate, thus giving distinct characteristics of all three seasons. Winter starts from mid - October to February, which is the season of the northeast monsoon. It is cold and dry, and the coldest month is January. Summer is from February to mid - May, with April being the hottest month of the year. The last is rainy season, which starts from mid-May to mid-October. It is the period when the southwest monsoon blows into Thailand. The weather is humid and rainy throughout the season, with an average annual rainfall of about 3,059 millimeters. The heaviest rain is in September. The average temperature is around 28 degrees Celsius, with a minimum of 21 degrees Celsius.

Flora and Wildlife
      The forest of Khun Song National Reserved Forest had been through logging concessions. According to the survey, all three forest categories are as follows :
        1) Tropical rain forests are found in lowlands, valleys, and foothills. This type of forest is important for economy and ecology because there are a variety of economic plants. The lower ground plants include Salacca wallichiana, different kinds of Rattan, and Bustard Cardamom.
        2) Dry evergreen forest is found at foothills and is present in fewer areas than tropical rain forests. Plant community structure is composed of four layers: the upper layer, the middle layer, the lower layer, and the undergrowth layer.
         3) Deciduous dipterocarp forest is a plant community that is rarely found. The dominant

        plants are Dipterocarpus intricatus Dyer., Patana oak, Great Elephant Apple, Burmese Sal, Shorea, Shorea siamensis Miq, and Nux-vomica Tree Lower ground plants are cogongrass, Curcuma sessilis, Scleria levis Retz, and Desho Grass. The critical wildlife in this area is mainly mammals, such as Asian elephant, Sambar deer, Barking Deer, Banteng, Gaur, Tiger, and Bear, and bird species such as Hornbills, Common Hill Myna, Asian Woollynecks, Siamese Pheasants, and Silver Pheasants.