During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee.

The river name is derived from snild which comes from the word snjallr which means "fast" (related to German schnell).

On 19 August 1938, a royal resolution changed the spelling of the name of the municipality to Snillfjord.

The official blazon is "Vert, a pitchfork argent" (Norwegian: I grønt et sølv greip).

The pitchfork has a tincture of argent which means it is commonly colored white, but if it is made out of metal, then silver is used.

The municipality of Snillfjord was located south of the Trondheimsleia and east of the Hemnfjorden.

The island of Hemnskjela lies in the Trondheimsleia in the north, and it is the southern entrance to the Hitra Tunnel.

The highest point in the municipality was the 791.7-metre (2,597 ft) tall mountain Gråurda.

The municipal council (Kommunestyre) of Snillfjord is made up of 17 representatives that are elected to four year terms.