Roi Et lies on a flat plain about 150 metres (490 ft) above sea level.

[5] At the center of Roi Et lies a lake, next to a 101 meter observation tower that is modeled in the shape of a traditional circular panpipe.

The monsoon season runs from May through October, with heavy rain and somewhat cooler temperatures during the day, although nights remain warm.

Route 214 leads north to Kalasin and south to Kaset Wisai, Surin, and Prasat.

Route 23 leads west to Maha Sarakham and Ban Phai, and east to Yasothon and Ubon Ratchathani.