Chaloem Rattanakosin National Park is located in the western mountains, which are  complex mountains landscape with karst topography. The altitude is between 240 to 1,260 meters above sea level and consists of Khao Kamphaeng, Khao Mai Hom, and Khao Phu Chang Mop. The highest point is the Khao Kamphaeng summit, which is about 1,260 meters above sea level. These mountains are the catchment area for Mae Phlu Creek, Takuat Creek, Mae Kra Phroi Creek and  Kra Phroi Creek.

Northern Border Contact: Adjacent to the National Reserved Forest, the 6th plot of Thai Paper Factory, Khao Chot Sub-district.

Southern Border Contact: Nong Ri National Reserved Forest, Khao Chot Sub-district, Si Sawat District in Kanchanaburi Province.

Eastern Border Contact: Nong Ri National Reserved Forest, Khao Chot Sub-district, Si Sawat District in Kanchanaburi Province.

Western Border Contact: Salak Phra Wildlife Sanctuary, Khao Chot Sub-district, Si Sawat District in Kanchanaburi Province.

     The climate of this area is influenced by the southwest and northeast monsoons. May to November is the southwest monsoon season which causes high humidity, heavy rains, and cloud cover, with an average rainfall of 1,700 milimeters per year. November to February is the northeast monsoon season when the weather is colder and sunny, with an average minimum temperature of 16 degrees Celsius in December and January. Summer is in March and April and has an average high temperature of 37 degrees Celsius.

      Chaloem Rattanakosin National Park is part of the Western Forest Complex and is home to four types of forest: hill evergreen forest , dry evergreen forest, mixed deciduous forest, and deciduous dipterocarp forest.
In the hill evergreen forest ecosystem, which is found around the hills and near the Khao Kamphaeng summit, it is at elevation of 1,000 to 1,257 meters above sea level.
It has important plants such as Evergreen Chinkapin (Castanopsis acuminatissima (Blume) A.DC.), Castanopsis diversifolia (Kurz) King ex Hook. f., Schima wallichii Korth, Protium serratum (Wall.) Engl, Cinnamon, Siam Benzoin, Podocarpus neriifolius, Syzygium cumini Baccaurea ramiflora Lour, and Dipterocarpus tuberculatus. Ground plants include Catunaregam tomentosum (Kurz) Bakh.f., Pavetta pilosa Craib, Ixora chinensis Lamk, Bustard cardamom, Amomum testaceum Ridl., Paco Fern, Crypsinus oxylobus (Wall. ex Kunze) Sledge, Mnesithea glandulosa (Trin.) Kon. & Sos., and Scleria levis Retz. as well as vines including Vitex siamica F.N. Williams, Thunbergia similis Craib, Gnetum montanum Markgr., Smilax corbularia Kunth, and Calameae.
      The epiphytic plants found include Cymbidium finlaysonianum, Dendrobium dantaniense, Rhynchostylis gigantea and Aerides odorata Lour. Animals that live there include Pig-Tailed Macaque, Ursus malayanus, Martes flavigula, Black Giant Squirrel, Serows, Oriental Pied Hornbill, Great Hornbills, and Minivet

    In the valley areas, there is deep topsoil, which is moist due to the high humidity, especially in places such as the Rim Huai Mae Phlu Valley, Mae Kra Phroi Creek, Kra Phroi Creek, and the surrounding forests of Khao Kamphaeng summit, next to the hill evergreen forest, between elevations of 200 to 1,000 meters above sea level. This area covers with dry evergreen forest with major plants such as Yang, Dipterocarpus turbinatus C.F., Paldao, Pterocymbium tinctorium (Blanco) Merr., Aphanamixis polystachya, Siamese Rough Bush, Syzygium megacarpum, Sugar Palm, Iron Wood, and Chukrasia tabularis A.Juss. . The epiphytic plants are the Dendrobium Orchid, Rhynchostylis Orchid, Oak-Leaf Fern, Hoya  Mirabilia Kidyoo, American Elder, Bird's Nest Fern, Holttum's Staghorn-fern, and Dischidia Major (Vahl) Merr. Vine plants include Bauhinia scandens L. var. horsfieldii., Entada glandulosa Pierre ex Gagnep., Calamus viminalis Willd, Bushwillows, Sappan tree, and Getonia floribunda   Roxb. The lower ground plants found include Ixora chinensis Lamk, Lime Berry, Bandicoot Berry, Diospyros undulata Wall. ex G. Don , Sand Ginger, Bustard Cardamom, Lasia spinosa (L.) Thwaites, Musa acuminata ,  Vietnamosasa cililta  (A.Camus) T.Q. Nguyen, Common reed , and Ludwigia hyssopifolia ( G. Don.) Exell. As the canopy of the trees are closely connected, the area is moist and is home to a variety of wildlife species, including White-Handed Gibbon, Pig-tailed Macaque, Black Giant Squirrel, Great Hornbill, Spotted Dove, and Blue-winged Leafbird., Wild Boars and Sambar Deer use the mud reservoirs for wallowing.
          The mixed deciduous forest plant community covers most of the National Park area at heights of between 300 to 1,000 meters above sea level. Among the common plants in the dry evergreen forest and the deciduous dipterocarp forest are Lagerstroemia  loudonii Teijsm. & Binn , Terminalia alata Heyne ex Roth, Iron Wood, Dalbergia oliveri Prain ,Irvingia malayana Oliv. ex A. Benn., Pterocarpus macrocarpus Kurz, Stereospermum neuranthum Kurz, Bombox anceps Pierre, and Croton roxburghii N.P. Balakr..

           Ground plants include the Dendrocalamus strictus (Roxb.) Nees, Bambusa bambos (L.) Voss, Thyrsostachys siamensis Gamble, Gigantochloa albociliata (Munro) Kurz, Gigantochloa densa , Ixora chinensis Lamk., Bandicoot Berry, Canthium parvifolium Roxb.., Aglaonema nitidum (Jack) Kunth, Kaempferia roscoeana Wall, and Tillansia usenoides L.
Climbers and epithelial plants, and there are also Senegalia megaladena (Desv.) Maslin, Capparis sepiaria Linn, Ascocentrum, Cymbidium finlaysonianum, Calameae, and Leopard Lily.

         Wild animals that live in the mixed deciduous forests include Asian Elephants, common Wild pig, Barking Deer, Banteng, Asiatic Brush-pailed porcupine, Malayan Porcupine, Burmese Hare, Red Junglefowl, Kalij pheasant, and Woodpecker.
The deciduous dipterocarp forest plant community in the National Park is the smallest, with some scattered on the top of mountains surrounded by the mixed deciduous  forests with above 600 to 1,000 meters. Plants include Burma Sal, White- Meranti (Shorea talura), Hairy Keruing, Dipterocarpus tuberculatus Roxb, Phyllanthus emblica L., Cratoxylum formosum (Jacq.) Benth. & Hook.f. ex Dyer, Phoenix acaulis Ham., Cycas circinalis L. , Curcuma sessilis Gage. , Yellow berried nightshade, Village Ardisia , Congea tomentosa Roxb., Vietnamosasa pusilla and Carex baccans Nees.

           Than Lot Noi Cave and Than Lot Yai Cave are home to a variety of wildlifes such as Blue Whistling Thrush, Hipposideros armiger , Giant Jungle Toad, Elaphe Radiata, Apis dorsata frabicius, and a many fish in the stream flowing through the cave, such as Minnows, Goldfin Tinfoil Barb, and Rasbora paviei , including shrimp. In the open areas next to the forest, visitors can see Vanellus indicus, Greater Coucal, and  Asian Grass Frog. In the areas adjacent to villages and farms, visitors can observe Wild Deer, Barking Deer, Wild Boar, and birds such as Sooty-Headed Bulbul, Brown Shrike, Indian Roller, Calotes versicolor, Tokay Gecko, and Asian Common Toad.