The cornerstone of the present Adair County Courthouse was laid in downtown Greenfield on July 4, 1891. The cornerstone features historical items including a bible; bottles of wine, corn, and oil; the history of Greenfield; and a letter to be opened by the oldest man present when removed. The $27,000 courthouse was designed by S.E. Maxon of Council Bluffs, the firm which also designed the Fremont County Courthouse in Sidney.