The province is in the Mekong valley. In dry season, from February to May, water in Mekong River declines, and allows islands to appear. Islands include Kaeng Tanglang at Si Sombun Village, close to Amphoe Chanuman, and Kaeng Hin Khan at Ban Hin Khan, 30 kilometres south of Amphoe Chanuman. The other two rivers in the province are the Lam Sae Bok and Lam Sae Bai.