Ceiriog was a rural district in the administrative county of Denbighshire from 1935 to 1974.
The rural district was formed by a County Review Order in 1935 from the merger of Chirk and Llansillin Rural districts.
The district was named after the Ceiriog Valley.
The district contained nine civil parishes: The rural district was abolished in 1974 by the Local Government Act 1972, with its area becoming part of the district of Glyndŵr, one of six districts of Clwyd.