The present courthouse was built by contractor J.F. Atkinson of Marshalltown for $48,000 in 1891 and 1892. T.D. Allen of Minneapolis was its architect. Allen also designed the Dickenson and Franklin County Courthouses during these years. Architecturally the courthouse is an amalgamation of several styles. The imposing brick and stone edifice in common to Richardsonian Romanesque. Romanesque arches, resting upon polished red granite columns, grace the north and south entrances. But the corner turrets, hipped roof, cross gables, and cut stone trimmings are Queen Anne features. The building originally had size tall ornamental brick chimneys, and a small cupola, which are also Queen Anne traits. The imposing 128 foot high clock tower is reminiscent of Italian gothic town centers. The building exterior is composed of St. Louis pressed brick and pink Kasota stone. Semi-circular transoms adorn the upper middle east and west windows. These transoms feature the great seal of the State of Iowa, etched onto frosted glass. A statue depicting Justice, Mercy, and Liberty stands enshrined in an alcove beneath the clock tower.
The cornerstone was laid amidst Masonic ceremonies on April 20, 1892. County Auditor Stephen Whited wrote a detailed history of the prior courthouses. It, along with numerous other documents, was sealed in that cornerstone. The cornerstone bears the Masonic emblem. No record of the artifacts was kept.
In 1921, the Wisner Opera House, an Eldora showplace, caught fire and burned to the ground. Fire spread to the courthouse clock tower, reportedly on a pigeon’s flaming wings. The entire courthouse roof and clock were destroyed, but the fire was contained by the clock tower's iron floor.
The ravages of time had done their work when the State Fire Marshall reported the courthouse interior was unsafe in 1967. The next Grand Jury concurred, and reported that the courthouse had fallen into a sad state of disrepair. The citizens of the county responded by giving a bond issue for renovation their 75% approval in the 1968 general election. R.D. Steward, Inc. of Marshalltown received the contract for the project. Iowa State University Professor Donald McKeown served as the project architect. County officers were moved out during the renovation between July 1969 and October 1970.
Steel and concrete replaced the wooden floor and ceiling supports from the original construction. The octagon-shaped open rotunda between the first floor and attic spire was filled in. Much of the original carved read oak woodwork was preserved and can still be seen in the rotunda area. An elevator was installed, and the wood window sashes were replaced with aluminum. The electrical wiring and heating systems were refurbished. The old courtroom received a complete make-over, with the judge's bench and bar being loaned to the Iowa State Fair in Des Moines. A round courtroom took its place, based upon a Frank Lloyd Wright courtroom in California.
The final cost of renovation totaled $422,000, a bargain compared to the cost of a new building. But the people of Hardin County also showed a commitment to their heritage in saving their courthouse from the wrecking ball. A landscaping project followed with $45,000 in private donations, and Pioneer Plaza was dedicated in 1971.
The Hardin County Courthouse was placed on the National Register of Historic Places in 1981. It still stands as a monument to the pride which rural Iowans have always had in their communities.