Roi Et is one of the provinces of Thailand, located in the northeastern part of the country. The province shares border with the provinces of Kalasin, Mukdahan, Yasothon, Sisaket, Surin and Maha Sarakham. Roi Et means 101, which refers to the original 11 satellite cities around the main city and the 11 gates of the same. The province has been divided into twenty districts and 193 sub districts. According to its area Roi Et is considered as one of the largest provinces of Thailand.

Roi Et is the name of the northeastern provinces of Thailand. Most of the province is covered by plains around 130-160 meters above sea level, drained by the Chi River. In the north of the province are the Phu Phan mountains, the river Yang. In the south is the Mun River, which forms the boundary with the province of Surin. At the mouth of the Chi River, where it meets the Mun river, a large flood basin that offers an excellent area for rice cultivation.