is a district located in Okayama Prefecture, Japan.
As of 2003, the district has an estimated population of 31,845 and a density of 79.65 persons per km2. The total area is 399.83 km2.
Aida District consists of the following village:
Prior to March 31, 2005, Aida District included
On that date, all but Nishiawakura merged to form the new city of Mimasaka.