Conception Bay, inlet (50 mi/80 km long, 20 mi/32 km wide at entrance), SE N.F., Canada, in N part of Avalon Peninsula, 10 mi/16 km W of St. Johns; 47°45'N 53°00'W. Near SW shore is Bell Isl., with once important iron mines. Chief towns on bay are Harbour Grace and Carbonear. There are numerous fishing settlements.