The history of Immaculate Conception Parish dates back to the late 1800's when a small, but staunch group of Catholics settled in Union. These faithful would journey five miles northwest to St. Gertrude's, or five miles East to St. John the Baptist, Gildehaus for Sunday Mass. In 1866, during the visit of the Vicar General to Krakow, the Catholics of Union asked permission to organize a parish of their own. The building that had served as the Presbyterian Church was purchased on the corner of State Street and Church. On Dec. 26, 1866, St. Mary's Catholic Church of Union was born. Diocesan priests from St. John's, Gildehaus first ministered to the new congregation which at that time was very small, but mass was only able to be offered once a month due to a shortage of priests. In 1870, the Jesuits from St. Francis Borgia Parish, Washington, were placed in charge of the little parish of St. Mary's. Jesuit fathers served the parish from 1870-1894. As early as 1882, a growing parish family saw the need for a larger house of worship and plans were made to build a new Church after a generous parishioner donated the present block where Immaculate Conception Church and Rectory now sit. In 1894, when St. Francis Borgia was placed under the direction of the Franciscan Fathers of the Sacred Heart, all surrounding missions were included. Thus began a legacy of the Franciscans caring diligently for the people of St. Mary's, Union. The pastor of St. Gertrude's, Krakow, had charge of the mission in Union until 1900 when the Archbishop turned over St. Gertrude's to diocesan priests. For several months, Union was served by the pastor of St. Ann's in Clover Bottom. As 1901 dawned, the first resident pastor was appointed to reside in Union. He soon began plans to build a new Church. The cornerstone was laid on June 30, 1901. The first Mass was celebrated in the beautiful new stone structure on May 4, 1902. The formal dedication took place, June 1, 1902. During the ceremony, the parish was rededicated to Our Blessed Mother under the title of her Immaculate Conception. From that time on St. Mary's Parish, Union, became Immaculate Conception Parish. Plans soon began for a school. The Church basement was completed and the first school for Catholic youth was begun. In October, 1902, 30 students formed the student body of Immaculate Conception School. Over the next several years enrollment increased necessitating the hiring of an additional teacher. In 1905, after a parish-wide meeting it was decided to build a school and invite the Franciscan Sisters of Lafayette, Indiana to begin teaching the students. The school was completed on August 1, 1905 and three sisters arrived shortly after. Several Franciscan pastors served Immaculate Conception from 1906 until 1928, when Fr. Hubert Pfeil, OFM became the Seventh Pastor. For nearly twenty years Fr. Hubert labored to provide for both the spiritual and physical needs of a growing parish family. It was Fr. Hubert who envisioned a new, larger Church to serve the needs of a growing population. He purchased the Mintrup property adjacent to the school and after minor renovations provided it to the Sisters as a new convent. 1948 was a momentous year for Immaculate Conception Parish. After nearly half a century of ministry by Franciscan pastors, Archbishop Joseph Ritter appointed the first diocesan priest to serve as pastor of the Catholic community of Union. Fr. Lawrence Rost assumed the parish shortly after Easter, 1948. By fall of the same year, permission was obtained to begin constructing the present Church of the Immaculate Conception that Fr. Hubert had envisioned. In April, 1952 the Archbishop was present for the ground breaking and the cornerstone was laid for the Church June 15, 1952.

Fr. Rost served I.C. for three more years until Fr. Raymond Schuermann became the Ninth Pastor. The pastoral duties of the time involved reducing the debt and planning for more classrooms for a growing school population. A new School wing and Parish Center were begun in the Spring of 1961 and the project was completed for the opening of school in 1962. In January, 1966 Fr. Sylvester Schiene began his pastorate, replacing the beloved Fr. Schuermann. The '60's were a time of change for the Catholic Church and Fr. Schiene set about the task of renovating Immaculate Conception to reflect the new vision of the Second Vatican Council. English replaced Latin, the altar was brought forward and the priest faced the people, and the people were encouraged to exercise a more active role in the celebration of the Eucharist by various new ministries. Renovations were also needed and made to the school facilities to improve the environment for our youth. After seventeen years as pastor, Fr. Schiene was replaced by Fr. Ted Burghoff in June of 1983. A genuine pastor to his flock, Fr. Burghoff is remembered for his warm sense of humor and broad smile. His tireless work of visiting the flock entrusted to his care allowed him to be a good shepherd, well respected in the local community by Catholics and non-Catholics alike. In his years as pastor, Fr. Burghoff made minor renovations to the Church. The marble communion rail was removed after pastoral catechesis emphasizing that no barriers ought to divide the Vatican II worship space. In 1990, after planning and mounting a very successful fund-raising drive, ground was broken for yet another new school addition to provide more classroom space, a science lab, a library, computer room, meeting room and faculty lounge. Throughout the difficult process of this sometimes controversial project, Fr. Burghoff ably led parishioners to realize a much needed and improved school facility. Due to health reasons, Fr. Burghoff retired as pastor in December of 1992. His farewell was a testimony to how much he had been a part of so many people's lives. The school gym was filled with well-wishers. Fr. Jerome D. Billing, having served in the Metropolitan Tribunal of the Archdiocese for 17 years was assigned to be the twelfth pastor of Immaculate Conception and assumed duties in February 1993. His financial expertise allowed the parish to quickly retire the debt owed on the 1991 school addition. The Church organ needed to be replaced, and by Easter, a new three-manual instrument was installed in a newly renovated choir loft. Talented carpenters from the parish designed and constructed organ speaker cabinets above the side altars and soon new statues of the Blessed Virgin and St. Joseph were purchased. The interior of the Church was deemed in need of repair and repainting. By Christmas, 1994 Immaculate Conception Church became the most noble Church of Franklin County. Having completed much needed improvements to the East side of Washington Avenue, Fr. Billing was approached to complete the original dream of the 1991 building committee, namely a Parish Center. In late summer of 1995, ground was broken to begin this project. The new Parish Center was dedicated by Bishop Paul Zipfel in September 1996. The cornerstone said it all, "By You, for You." Having served I.C. parish for four and a half years, Fr. Billing was asked to return to work in the Metropolitan Tribunal.

In June of 1997, Fr. Peter M. Blake, became current pastor of Immaculate Conception. Having served as Parochial Vicar under both Fr. Burghoff and Fr. Billing, for five years, his appointment as pastor came as an unusual move, but well received by both the parishioners and him. Fr. Blake is the 13th Pastor of Immaculate Conception, Union.

In June of 2001, Fr. Matthew M. Mitas was appointed 14th Pastor of Immaculate Conception. His instillation took place on Sunday, July 29, 2001.

From the original twelve families in 1866, Immaculate Conception Parish has continued to grow as a community of Catholic Christians. Now ready to face a new millennium with faith, hope and love for our Lord Jesus Christ and His Church, we are a parish of nearly 1,000 families and still growing; building upon the rich heritage of the past and committed to our charge by God for the future.