Its main attraction is Kuusisto Castle.

The island was a part of the Piikkiö parish.

Kuusisto gained chapel rights in 1653, eventually becoming a separate municipality and parish in 1914.

[5][6] As the municipality was disestablished before rural municipalities were allowed to use coats of arms, Kuusisto never had an official coat of arms.

The heraldist Tapani Talari has designed an unofficial coat of arms for use by the Suomen Kuntaliitto ry.