Located between Dubuque and Maquoketa on U.S. Highway 61 is the small town of Zwingle, population 91, which has the distinction of being alphabetically the last community in the state. Less than 10 years after the area of Zwingle was first settled, construction began on a modest, 1,200 square-foot church building in September 1855.  The $1,500 facility was dedicated in May 1856, and held the distinction of being the first reformed church constructed west of the Mississippi River; it has since been significantly expanded and renovated.

Along with the building, the three-acre church site also contains a cemetery and a parsonage, which was constructed in 1976, six years after the Harmony Church formally began its affiliation with the United Church of Christ.  While the membership once exceeded 200, the church now has about 50 members.