In a land area of 83,457 square kilometers, the diocesan territory covers Sapporo and other cities such as Ishikari, Ebetsu, Kitahiroshima and others.
In the territory of Sapporo diocese, the population is 5,371,154 at end of 2017. Most residents are ethnic Japanese. This includes the indigenous Ainu people, with their own languages. There were also 21,318 non-Japanese people in the area, according to Immigration Bureau of Japan.
The Apostolic Prefecture of Sapporo was established on Feb. 12, 1915. It was separated from the Hakodate Diocese and included all of Hokkaido (except the district of Hakodate) and the southern part of Sakhalin. It was entrusted to the Order of Friars Minor of Fulda Province, Germany. Msgr. Wenceslaus Kinold, O.F.M., was appointed Apostolic Prefect. On March 30, 1929, it was raised to the status of Apostolic Vicariate and Msgr. Kinold was consecrated bishop.
On July 14, 1932, when the southern part of Sakhalin became independent, the Apostolic Prefecture of Sakhalin was established and was transferred to the care of Polish Franciscans.
Upon the resignation of Bishop Kinold as Apostolic Vicar , Msgr. Tatewaki Toda became Apostolic Administrator in 1941. In 1944 Msgr. Toda was transferred to the Yokohama Diocese and Msgr. Isamu Seno was appointed Apostolic Administrator.
On Dec.11, 1952 the district of Hakodate, which had belonged to the Sendai Diocese, was incorporated and Sapporo was raised to the status of a diocese that included all of Hokkaido. Father Takahiko Tomizawa was appointed the first bishop of the new Sapporo Diocese and consecrated on March 19, 1953.
With the resignation of Bishop Tomizawa, Father Toshio Jinushi was appointed as his successor on Oct. 3, 1987, and consecrated on Jan. 15,1988.
On Nov. 17, 2009 it was announced that the resignation of Bishop Jinushi was accepted and Most Rev. Isao Kikuchi, Bishop of Niigata, was appointed as Apostolic Administrator of the diocese. (Catholic Bishops' Conference of Japan, 2010)
The diocesan territory is linked by air planes, railways and buses.
Throughout Japan, literacy is 99 percent according to Central Intelligence Agency, USA, 2010.