Named for one of the framers of the Texas Declaration of Independence, Dimmit County was created from four other counties in 1858, formally organized in 1880, and given Carrizo Springs as its county seat. On November 12, 1883, the county commissioners court chose architect Alfred Giles to design a permanent courthouse, but on November 26 reversed that decision and selected J.C. Breeding & Sons of San Antonio as both architects and builders. Probably working from Giles' initial plans, they erected a courthouse with a double gallery porch whose cubical form and Italianate detailing resembled Giles' other Texas courthouse designs of the same period. By the 1920s, the county's growth required a larger government building, and Henry T. Phelps designed an expansion. Under his direction, the San Antonio Construction Company demolished the north second story wall, removed exterior rock from the lower north and south walls, and added longer wings at each end. Following his usual Classical Revival approach, Phelps created a symmetrical façade, moved the main entrance to the west side, emphasized it with four massive columns and a recessed porch, widened the nineteenth-century windows, and replaced the Second Empire roofline with an elaborate cornice, transforming the building from a simplified late-1880s Italianate style to the restrained Classicism popular in the 1920s.