In 1852, the first Swedish settlers made their way west in search of a site where water, wood, and tillable land was available for the establishment of homes.  Being deeply religious people, these settlers gathered in the different close-by school houses and homes for worship under the direction of S. P. Sandeen.

By the mid-1860s, the settlement in the Amityville area was large enough to meet for corporate worship. In 1868, Rev. B. M. Holland, the first ordained pastor in Burlington, assisted with the organization of the congregation known as the Swedish Evangelical Lutheran Church of Amityville (this congregation became Immanuel Lutheran Church of Mediapolis).  The constitution was adopted on the second day after Christmas and signed by forty charter members.  On May 10, 1869, the congregation decided to become affiliated with the Augustana Synod.

Construction on the first building was completed on August 20, 1872.  The first pastor was called on January 11, 1875.  Rev. Nels Forsander served the congregation until 1881.  During this time, a parsonage was built.  In 1873, additional land was purchased to lay out a cemetery under the Swedish plan.

In the late 1880s, the congregation decided to move into Mediapolis since it was centrally located, had a railroad and a post office.  The new church building was completed in 1890.

On January 8, 1908, the women of the congregation won the right to vote on church affairs.

By the 1940s, the small frame church, which had served the congregation faithfully for many years, had become inadequate because of its lack of facilities for Sunday School and fellowship.  There were also structural issues beginning to surface as the building aged.  On January 9, 1945, the congregation voted to make plans to build a new church building as soon as possible.

Final services were held in the old church on October 4, 1953.  The next morning, men and women removed the furniture and furnishings from the building and began the tearing down process.  On October 11, just one week after the final services in the old church building, groundbreaking services were held on the site where the old building had stood.  Both men and women worked on the tear-down and construction of the building as well as the refinishing of many of the congregation's furnishings.  The first worship service was held in the new building on October 3, 1954 (one year after the last service in the old building).  The new church building was dedicated on March 27, 1955.

In 1966, St. Paul Lutheran Church in rural Sperry, Iowa was closed.  At that time, the members and history of St. Paul’s became part of Immanuel.  This history is remembered by an annual service at St. Paul’s during September.  With no electricity and the old church building, this worship service is a step back to another time.

In 1993, Immanuel celebrated its 125th anniversary with special events and celebrations at the original congregation site in Amityville as well as at the current congregation home in Mediapolis.

On November 11, 2018, Immanuel celebrated its 150th anniversary of “Praising God and Serving People.”  A special worship service was held, an anniversary banner was created and a catered luncheon served to everyone who attended worship that morning.  A lot of visiting was done by returning members, former pastors and their families, and ministry partners.