Cadiz ( /kædɪs/) is a village in Harrison County, Ohio, United States. The population was 3,308 at the 2000 census. It is the county seat of Harrison County.
Cadiz is located at 40°16′15″N 80°59′45″W / 40.27083°N 80.99583°W / 40.27083; -80.99583 (40.270713, -80.995709).
According to the United States Census Bureau, the village has a total area of 8.9 square miles (23.1 km²), of which, 8.8 square miles (22.9 km²) of it is land and 0.1 square miles (0.3 km²) of it (1.12%) is water.