Trígono is a former municipality in the Evros regional unit, East Macedonia and Thrace, Greece. Since the 2011 local government reform, it is part of the municipality Orestiada, of which it is a municipal unit. The municipal unit has an area of 392.538 km2. The seat of the municipality was in Dikaia. The municipality was created in 1997 under the Capodistrian Plan. Trigono is the country's northernmost municipal unit, situated in the triangle between the rivers Evros and Ardas. It borders Bulgaria to the north and west, and Turkey to the northeast. The nearest cities are Svilengrad (Bulgaria) to the north, Edirne (Turkey) to the east, and Orestiada to the southeast. The area consists mainly of low hills, with plains in the river valleys, and higher elevations up to 400 m towards the west.