O'Reilly is an unincorporated community located in Bolivar County, Mississippi, United States, along U.S. Route 61. O'Reilly is approximately south of Boyle and approximately north of Shaw. O'Reilly is located on the former Yazoo and Mississippi Valley Railroad. A post office operated under the name O'Reilly from 1903 to 1926. References Unincorporated communities in Bolivar County, Mississippi Unincorporated communities in Mississippi