Long before there was a Catholic Church in Jacksonville, Catholic families gathered in their homes to celebrate Mass with a priests who traveled on horseback from Georgia. This period extended from 1829 to 1854.
By 1854, Catholics moved from celebrating Mass in their homes to a small wooden building on the corner of Ocean and Duval streets. This was also the year that Pope Pius IX declared that the IMMACULATE CONCEPTION of the Blessed Virgin Mary was now an Article of Faith.

It was fitting, therefore, that the new wooden church building in Jacksonville be named in honor of the new Marian dogma. In fact, William J. Hamilton, a priest from the Diocese of Savannah, was sent to Jacksonville to dedicate the church and become its spriritual leader. He exhibited a singular facility for ecumenism which so many of Immaculate Conception's pastors carried on through the years. Father Hamilton was, as an observer put it, "a man of amiable and social qualities that endeared him to all, irrespective of creed."
Following 1857 when Florida was made a Vicariate Apostolic, "Cowford," as Jacksonville was known at that time, became part of the new Vicariate.

The 1860s were perilous times for the nascent church and for Jacksonville as a whole. In 1863, the town was occupied by Union troops and they prosecuted the "war Between the States." Sadly, some intolerant members of the bivouacked troops decided that the gates of hell shall prevail on the "beautiful little cottage" that the Catholics were using as their church. The entire building was sacked, with Union soldiers marching through town wearing sacred vestments and blowing notes through organ pipes pulled from the church.
After the war, Church officials requested reimbursement for damages by the U.S. government, but their demands fell on deaf ears. Regardless, the parish moved forward and established a school in 1868 under the direction of the Sisters of St. Joseph.

Fortune shone on Immaculate Conception Parish during the next 35 years as men such as Father John Kenny -- later a bishop -- Father Michael Maher and Father James J. Meehan led the parish into its maturity as a religious cornerstone of downtown Jacksonville. Immaculate Conception was also the mother church of many of the first parishes which were established in the city's first suburbs. from 1881 to 1964 it operated a school that early in its history also included high school classes.

The present church edifice was dedicated in 1910 on the Feast of the Immaculate Conception. The former pastor, Bishop Kenny, presided at the dedication of the church which is constructed of white Kentucky limestone. Its interior is decorated with fine stained glass windows produced in Munich, Germany by the Mayer Stained Glass Company. At the time, Immaculate Conception was the tallest building in the city.
In modern times, "I.C.," under the leadership of its current pastor, Father Antonio Leon, has become the cornerstone of Jacksonville's Catholic community and has more than 800 registered families.