Ogdensburg, [350]

Ohio River, [128], [130], [133], [224], [226], [241]

Olier, Jean Jacques, [75], [76]

Onondaga, Lake,98

Onondagas, [55], [98], [99], [100]

Ontario, [84], [127], [312], [315], [316], [338], [349]

Ontario, Lake, [54], [57], [127], [129], [134], [349]

Oregon, [406], [407]

Orleans Island, [13], [76]

Oswego, [247], [250]