The municipality of Tres Islas is one of the municipalities of Cerro Largo Department, Uruguay, established on 30 October 2018.

Its seat is the town of Tres Islas.

This municipality was created on 30 October 2018 by Departmental Board of Cerro Largo Decree No.

29/2018, covering the same territory of the electoral constituency identified by the Electoral Board of Cerro Largo as series GFA.

[3] The municipality is located at the west area of Cerro Largo Department.