Four streams flowed together to create our movement. The first was home-based Bible studies and communion celebrations “for all believers but believers only,” at a time when attendance in the Lutheran state churches of Sweden and Norway was required by law. When these finally organized as churches they were “free” from the control of the Lutheran state church. The second stream was the spiritual life of the Pietists in Europe in the 1800s, reinforced by the third stream – the revival fires of the Second Great Awakening in America. The final tributary was the political and economic distress throughout Scandinavia in the late 1800s that led over 2 million Swedes and nearly 1 million Norwegians and Danes to cross the ocean and come to America.
The official birthday of the Evangelical Free Church in the United States was 1884, when a meeting was held in Boone, Iowa. The sole intent of coming together was to be more effective in evangelism and missions, as reflected by the sending of the first missionary (J.H. Von Qualen) to Canton, China, in 1887.
“The Free Church was not organized as a denomination. Primarily it was intended to be a missionary enterprise… Although no definite organization was accomplished [at the 1884 Boone meeting], yet enough was done to mark the beginning of a more definite work… All were alive to the blessings bestowed; all were thrilled by the precious light shed upon and through the prophetic word, and all were on fire for the saving of as many souls as possible, and in as short a time as possible. Jesus was coming soon – that was the heart-throb back of it all. And that was sufficient.”
As wave after wave of immigrants came to the U.S., most Free Church work was dedicated to reaching these first generation families who still spoke their mother tongue. So it wasn’t until World War I brought a stop to immigration that the churches began to consider doing their worship services in English. By the 1930s and 40s most Free Churches had made the change, so a merger of the Swedish and Norwegian-Danish Free Churches (until that time mostly independent even from each other) was achieved in 1950 and the Evangelical Free Church of America was born.
For more details read: EFCAHistory
 The Golden Jubilee, E.A.Halleen, p. 27, 1934.