Derby is an unincorporated community along the Ohio River in far southern Union Township, Perry County, in the U.S. state of Indiana. It lies at the intersection of State Roads 66 and 70 above the city of Tell City, the county seat of Perry County. Its elevation is 453 feet (138 m), and it is located at 38°1′49″N 86°31′38″W / 38.03028°N 86.52722°W (38.0303400, -86.5272018). Although Derby is unincorporated, it has a post office, with the ZIP code of 47525.