The history of Immaculate Conception Church, Sumner, begins with the first Catholic settlement in LeRoy Township, Bremer County. Patrick and Mary (Foley) O'Day were the first Catholic pioneers in LeRoy township, arriving in 1854.
The nearby town of Sumner was platted in 1871 near the border of Bremer and Fayette counties. the Catholics in the Sumner area were served by itinerant priests until 1884, when Bishop John Hennessey appointed Father John Hogan to establish a parish in the town.
In 1894 the Catholic pioneers judged their numbers were sufficient to build a church. The church was a white frame building 30' x 50' with a seating capacity of 175 and had an entry and a belfry. The cost was $600. On November 13, 1894 the completed church was dedicated to the Blessed Mother under the title of her Immaculate Conception.
Over the intervening years the parish was shepherded by a number of priests. Father Hogan was succeeded by Father John J. Brogan, then Father John M. Molloy, Father Richard P. Murphy, Father Michael L. Kerper, Father John J. Leen, Father John M. O'Donnell, Father James L. Whalen, Father John J. Costelloe, Father John M. Fischer, and Father Herman J. Dietz. In 1950 Father Joseph J. Kleiner became pastor and served for the next 37 years. During these years the number of families in the parish almost doubled and a number of improvements were made to the church following a fire in 1956.
Father Paul J. Evans succeeded Father Kleiner in 1987. He was followed in 1988 by Father Kenneth C. Stecher and in July 1991 Father Joseph Heineman was appointed pastor. Father Heineman died on January 5, 1994.
Father John Purtell became pastor of Immaculate Conception on Feb. 7, 1994. Immaculate Conception celebrated its 100th anniversary on August 7, 1994. Father Purtell retired in July 2008, and Father James Brokman was appointed pastor.
A century after its founding, in 1994, a visionary seed began to germinate in the minds of the Immaculate Conception Church Council. The need to create a handicapped accessible church with expanded area for a gathering space became a dominant concern.
In January 1998 the expansion and extensively remodeled area were dedicated with Archbishop Jerome Hanus presiding. Total cost of the project was $256,094. the parish now enjoys a canopied entrance, an elevator which creates access to all levels, a visible choir area, and a large gathering area.
The parish presently consists of 178 households. It has had 18 members enter the religious life over the years, 5 priests and 13 nuns.