In 1837, Delaware County was established when Dubuque County was divided into a number of smaller counties. After that, the elected Delaware County commissioners were directed to meet and select a county seat. The first area selected was at Ead’s Grove, located in the Northeast part of Delaware Township.

Shortly after that, many of the residents requested a site closer to the center of the County near the present town of Delaware. The selecting committee wanted to locate the county seat in the geographical center of the county, but there was no timber or water in the center of the county. After visiting several locations, the committee was approaching the site of Delhi. Suddenly a deer sprang up and ran off. It was suggested that they kill the deer and stake a site at that location. This was done, and Delhi became the county seat for over 50 years.

As the county population grew, Delhi and Manchester have become the most important cities in the county. A battle over the county seat title developed between Manchester and Delhi. Several elections were held over the location of the county seat. Manchester failed all of them, except the last one held on November 2, 1880. Following this election, the citizens of Manchester quickly constructed a two-story frame courthouse, complete with a vault. This building was a temporary structure, and a more elaborate building was constructed in 1894. This courthouse, the fourth for Delaware County, was dedicated on January 7, 1895. Manchester has become the county seat ever since.

Today, Delaware County is a prime hotspot for outdoor activities such as fishing, hunting, camping, hiking, and much more. Delaware County also has the largest state park in Iowa – 1600 acres at Backbone State Park. Delaware County is home to approximately 17,764 people.