Founded by Luang Pu In (หลวงปู่อินทร์), a Buddhist monk who came from Nakhon Sawan along with his family in 1958.

In the north it borders with the Lan Krabue district (Chong Lom and Non Phluang).

Sai Ngam is divided into 10 villages and governed by two local administrative bodies.

Originally, Sai Ngam was the part of Nong Khla, Mueang Kamphaeng Phet, where located in the Reserve Forest area.

The name was later changed to "Sai Ngam", and it was separated from Nong Khla to become a subdistrict in 1958.