In 1880, the Dakotas were separated and the Diocese of Sioux Falls was established. Montana was dropped three years later. In 1885, the Diocese of Omaha, consisting of Nebraska and Wyoming, was established.
During Bishop O'Connor's administration, many of Omaha's older parishes were founded and the Franciscan Fathers arrived in the area.
After the Creighton family gave Bishop O'Connor the college they had endowed, Creighton University was entrusted to the Society of Jesus in 1878.
Bishop James O'Connor was appointed to replace Bishop O'Gorman in 1876.
