The municipality, consisting of the coastal settlements Drvenik, Zaostrog, Podaca, Brist and Gradac itself, marks the end of the riviera and the county.

[4] Municipality has very low density of permanent population (mostly native to Dalmatia, or the rest of Croatia and neighboring Bosnia and Herzegovina), with handful of people outside of the region.

The medieval town of Lapčan, or Labinac, which, under the name of Labineca, was mentioned by the Byzantine emperor Constantine VII Porphyrogenitus, mid-10th century, was situated on the territory of today's Gradac.

It was named after the stronghold that was situated on the elevation above the present-day church of St. Michael, and which was built probably during the Cretan War (1645–1669) as a defence against the Ottoman Empire.

The remnants of the old tower from the 16th century can be found in the abandoned village of Čista above Gradac, the seat of the ancient Fragostin's district.