In a land area of 4,737,997 square kilometers, the diocesan territory covers Akita, Yamagata and Niigata prefectures.
In the territory of Niigata diocese, the population is 4,570,000 at end of 2016. Most residents are ethnic Japanese. There are also 26,324 non-Japanese people in the area, according to the Immigration Bureau of Japan.
The territory also has many languages/dialects.
The Prefecture Apostolic of Niigata was established on Aug. 13 1912 and included the three prefectures of Akita, Yamagata and Niigata that had belonged to the Diocese of Hakodate as well as the three prefectures of Toyama, Ishikawa and Fukui that had belonged to the Archdiocese of Tokyo. It was entrusted to the German Fathers of the Society of the Divine Word.
When the Prefecture Apostolic of Nagoya was established on Feb. 18, 1922, Toyama, Ishikawa and Fukui were incorporated into it.
The first prefect apostolic, Monsignor Joseph Reiners, S.V.D. was succeeded by Monsignor Anton Ceska, S.V.D. in 1926. In 1941 Monsignor Ceska resigned and Monsignor Magoshiro Matsuoka, Prefect Apostolic of Nagoya, became the acting ordinary of the Prefecture Apostolic of Niigata as well. In 1945 he became simultaneously prefect of both apostolic prefectures. In 1953 Father Tokisuke Noda succeeded him as Prefect Apostolic of Niigata. In 1959 Monsignor Noda was nominated first Bishop of Hiroshima, but he excused himself because of illness. He died on Oct. 11, 1961 while still Prefect Apostolic of Niigata. After that, the position of ordinary was vacant, but on April 16, 1962 Niigata was raised to the status of a diocese and in June of the same year Father Shojiro Ito was consecrated bishop and assumed the position of Bishop of Niigata.
Bishop Ito resigned on March 3, 1985, and on June 9 of the same year Father Keiichi Sato, O.F.M. was consecrated bishop.
Bishop Sato resigned and Father Isao Kikuchi, S.V.D. Isao was appointed to succeed him on May 14 ,2004. (Catholic Bishops' Conference of Japan, 2010)
Air planes, railways and buses are in use in the territory.
Throughout Japan, literacy is 99 percent, according to the Central Intelligence Agency, USA, 2010.