 It was upgraded to a full district on 21 May 1990.Neighboring districts are (from the north clockwise) Dan Chang, Doem Bang Nang Buat, Sam Chuk, and Don Chedi of Suphan Buri Province, and Lao Khwan of Kanchanaburi Province

Nong Ya Sai is divided into six sub-districts ("tambons"), which are further subdivided into 66 administrative villages ("mubans").There is one sub-district municipality ("thesaban tambon") in the district