Kosamphi Forest Park is a forest park of approximately 125 rai located along the Chi River in Kosum Phisai District, Maha Sarakham Province. The area is a riverside forest that remains relatively well-preserved compared to the surrounding agricultural land. It consists of dry evergreen forest mixed with dry dipterocarp forest, with dense large trees that create a shady environment and a higher level of humidity than the surrounding areas.The internal forest structure is diverse, ranging from the canopy layer of large trees such as Yang Na, Takhian, and other riverside species, to the middle layer of shrubs and medium-sized trees, down to the understory consisting of ground plants and ferns that thrive in shaded conditions. The root systems of these plants help stabilize the soil along the Chi River, reduce bank erosion, and maintain the ecological balance of the riverside environment.

The area has a tropical monsoon climate with clearly defined seasonal changes. During the rainy season, the forest becomes lush and highly humid while the Chi River carries a high water level. In the dry season, the water level drops, revealing natural rock formations known as Tad Rock Rapids, which become a scenic resting and viewpoint area along the river. Transitional seasons are often the periods when wildlife and monkeys are most active.Kosamphi Forest Park was originally a public forest area known as Nong Boong Forest before being officially designated as a forest park on 1 October 1976 to conserve the Chi River riparian forest and serve as a local nature study area for communities and students. Although relatively small in size, it plays an important role as a green space that helps maintain the ecological balance of the local watershed.

The forest park is home to a large troop of long-tailed macaques with a clearly structured social system. Dominant males control territory and hierarchy, while females play a key role in caring for offspring and maintaining social bonds within the group. Most monkey behavior is learned through observation and imitation, resulting in relatively complex social interactions.A key highlight is the “golden macaque,” a rare color variation caused by pigmentation differences that give the monkeys a golden-yellow coat. They are not a separate species but a rare genetic variation found in this area, making them a unique feature of the park.Another important attraction is Tad Rock Rapids, a natural rock formation along the Chi River formed by long-term river erosion and sediment deposition. During the dry season, the receding water exposes a wide rocky surface where visitors can walk and relax, and it is also a popular gathering spot for local residents.

The area also represents a form of human–wildlife coexistence. Visitors can purchase food from local vendors to feed the monkeys; however, because the monkeys are highly accustomed to humans, they may approach or attempt to grab items, so caution is required.Overall, Kosamphi Forest Park is a natural attraction suitable for forest walks, riverside relaxation, and studying the real ecosystem of macaques in their natural habitat. The best time to visit is in the morning or late afternoon when the weather is cooler and animal activity is at its peak.

• By car: From Maha Sarakham city, take Highway 208 toward Kosum Phisai District for about 28 kilometers. The entrance is located opposite the district office, then continue about 450 meters inside to reach the forest park.

• By public transport: Take a Maha Sarakham–Khon Kaen bus and get off at Kosum Phisai District. Then take a motorcycle taxi to the forest park.

• Be careful of monkeys, as they may snatch food or belongings.

• Keep valuables such as phones, glasses, and hats secure.

• The best time to visit is in the morning or late afternoon when it is cooler and monkeys are more active.

• There is no accommodation available, so visitors must prepare their own camping equipment if staying overnight.

• Food for monkeys can be purchased from local vendors at the entrance of the park.

Admission fee:

• Free of charge (no admission fee)

Opening hours:

• Open daily from 08:30 AM to 04:30 PM