Sunamganj is the land of haor-baor, boro dhan, aaul-baul. There are various types of say about the name Sunamganj. Some says there was a Muslim soldier came here at 13th century named Sunamdi. By the rotation of time by his name, the name of this area was established Sunamganj. Some say there was a fisherman named Shunamdi who lived in the river Surma and later a business community was built up by him. So, for his honor, the name of the area is Sunamganj.