Also a small slice of land on the continent was part of the municipality.

The name Säynätsalo originally referred to the main island, which gets its name from säynäs meaning "ide" and salo meaning "island".

Another municipality named after the ide was Säyneinen in Northern Savonia.

The Korpilahti parish, including Säynätsalo, was split off from Jämsä in 1861.

[2] The businessman Johan Parviainen bought the island in 1897 and built a sawmill there in the next year.