Trio (/ˈtraɪoʊ/) is an unincorporated community in Williamsburg County, South Carolina, United States.

[2][3] In 1883 the Bryan brothers established a post office and officially named the community Trio, pronounced "Try-oh" in the local dialect.

[2] The two-story brick building that originally housed the Trio Post Office served multiple purposes for local residents throughout the twentieth century.

[3] It functioned as a rural store, health clinic, and financial institution, known as The Bank of Trio.

[3] The building is no longer in use today, and is in a state of disrepair, but remains a local landmark.