Abstract: Data for U, Th, and K, determined by epithermal neutron activation methods, are reported for Lower and Middle Dalradian lithologies from Co. Donegal, Ireland. Abundances are identical to rocks with stratigraphical correlation in the Scottish Dalradian and appear not to have been affected by regional metamorphism to biotite and possibly even garnet grade during the Grampian orogenic phase, or later contact metamorphism in the aureole of the Main Donegal pluton. Uraniferous Dalradian lithologies have not been encountered in Donegal. Incorporation of Dalradian rocks, either by assimilation or as extensive raft trains within the Main Donegal granite, is therefore unlikely to have contributed to the development of known pegmatite-hosted U mineralization associated with this late Caledonian pluton.