Sardis is a census-designated place in southeastern Lee Township, Monroe County, Ohio, United States. It is unincorporated, but has a post office with the ZIP code of 43946. As of the 2010 census, it had a population of 559.Sardis is at the intersection of Ohio State Routes 7 and 255, lying between Duffy and Fly.Among the early settlers in this area was Major Earl Sproat, one of the 48 members of the Ohio Company. The Ohio Company founded Marietta, the first permanent settlement in the Northwest Territory in 1788. The village of Sardis was laid out by James Patton in 1843.Sardis shares a high school, River High Local School, in the Switzerland of Ohio school district, with other nearby and riverfront communities including: Antioch, Duffy, Fly, Hannibal, Laings, Powhatan Point, and Clarington.Sardis is located at 39°37′22″N 80°54′44″W / 39.62278°N 80.91222°W / 39.62278; -80.91222. According to the United States Census Bureau, the CDP has a total area of 1.