On 1 January 1978, the parts of Vindafjord Municipality located southeast of the Vindafjorden on the Ropeid peninsula (population: 13) was transferred to Suldal.

The first element is the plural genitive case of súla which means "pillar" or "column" (likely referring to the mountain pass Suldalsporten).

The official blazon is "Gules, three bendlets wavy Or" (Norwegian: I raudt ein gull bølgjeforma trillingstreng, skråstilt høgre venstre).

This means the arms have a red field (background) and the charge is a set of the three diagonal wavy lins.

The area that is now Suldal municipality has a long history of trade connections to the nearby valley regions to the north and east.

At 1,736 square kilometres (670 sq mi), Suldal is the largest municipality in Rogaland county.

The municipality borders three counties: Vestland (north), Telemark (northeast), and Agder (east).

To the north, Suldal is bordered by Sauda and Ullensvang municipalities, in the east by Vinje and Bykle, in the south by Hjelmeland, and in the west by Vindafjord.

The finished hydroelectric complex has a total capacity of approximately 2,100 megawatts (2,800,000 hp) and produces about 4.8 terawatt-hours (17 PJ) yearly.