Kalasin Province, known as the "City of Black Water," is a historically rich area in northeastern Thailand. Its name derives from “Kaal” meaning “black” and “Sin” meaning “water,” a reference to the deep-colored local waters. Initially inhabited by the Lawa people over 1,600 years ago, Kalasin has a long heritage of human settlement. In 1777, the Lao noble Thao Somphamit led a group of people fleeing from conflicts in Vientiane to settle along the Pao River in present-day Kalasin, forming a community called "Ban Kaeng Samrong."

In 1793, Thao Somphamit presented gifts to King Rama I, pledging loyalty to the Chakri Dynasty. In return, the king formally established Kaeng Samrong as "Muang Kalasin" (Kalasin City) and appointed Thao Somphamit as the city’s first governor, titled "Phraya Chai Sunthorn." In 1913, under administrative reforms by King Rama V, Kalasin became a district of Roi Et Province, and later briefly part of Maha Sarakham Province.

Kalasin regained provincial status on October 1, 1947, reflecting its economic and cultural growth. Today, the province covers 6,947 square kilometers and is known for its fertile land, archaeology, and cultural ties to the Lao and Lawa heritage.