When Union County was formed, the struggle between the North and the South was at its height.  When Iowa Legislators met the preservation of the Union was foremost in their minds, and thus the name of Union County was born.

The county was established in 1851.  An election was held in Petersville on August 1, 1852, but it was not until February 15, 1855 that a county seat was selected.  The site that was chosen was Afton.  Two years later a two-story, frame courthouse was erected at a cost of $1,756.  This building was also used as a church and a school.

The town of Highland challenged Afton for the county seat in an election.  Afton remained the county seat, but by only 15 votes.  Highland soon declined, and most of its buildings were moved to Afton. 

Following this challenge the county constructed its second courthouse.   This building was larger and more elaborate than the first.   It was constructed of brick and was enhanced by a large cupola.  O. J. King was the contractor of the $25,000 building.

The town of Creston had been established, along the railroad, and it was suggested that the county seat be moved.  Creston had built a courthouse and offered it to the county.  The smaller city of Afton had nothing to offer and so Creston, following an election, became the new county seat on November 25, 1890.   The $22,000, two-story courthouse was used until 1951.  At this time the city and county joined forces to erect a modern office building.  This $300,000 structure is constructed of concrete and faced with limestone.  It houses both the municipal and county offices.