Sans Souci is an unincorporated community in St. Clair County in the U.S. state of Michigan.

The community is located along the St. Clair River on the eastern coast of Harsens Island.

[2] Sans Souci began as a shipping and trading center on Harsens Island.

[3] The community is served by the Harsens Island post office, which uses the 48028 ZIP Code.

The name Sans Souci is no longer acceptable for mail delivery.