Cobourg Island or Coburg Island (both: KO-buhrg) (22 mi/35 km long, 4 mi/6 km14 mi/23 km wide), E Franklin Dist., N.W.T., Canada, in Baffin Bay, at entrance of Jones Sound, bet. Ellesmere and Devon isls.; 75°58'N 79°30'W. Mountainous. Large numbers of murres breed here.