Nishiazai (西浅井郡, Nishiazai-gun) was a district located in Shiga Prefecture. The district is equivalent to the town of Nishiazai in Ika District.

• 1878 – Azai District splits into Nishiazai and Higashiazai Districts.
• April 1, 1889 – Municipal status is enforced. The villages of Shiotsu and Nagahara are formed.
• April 1, 1897 – Nishiazai District merges into Ika District.

• List of dissolved districts of Japan