Ōtsu (大津郡, Ōtsu-gun) was a district located in Yamaguchi Prefecture, Japan.
As of 2003, the district had an estimated population of 18,761.
On March 22, 2005, the towns of Heki, Misumi and Yuya were merged into the expanded city of Nagato.
Ōtsu District was dissolved as a result of this merger.
This article about a location in Yamaguchi Prefecture is a stub.