​GEROLSTEIN, a village and climatic health resort of Germany, in the Prussian Rhine Province, attractively situated on the Kyll, in the Eifel range, 1100 ft. above the sea, 58 m. W. of Andernach by rail, and at the junction of lines to Trèves and St Vith. The castle of Gerolstein, built in 1115 and now in ruins, affords a fine view of the Kyllthal. Gerolstein is celebrated for its lithia waters, which are largely exported. Pop. (1900) 1308.