Karnes County erected its first courthouse in Helena in 1854, when Helena was an important stage stop between San Antonio and Goliad. After that original courthouse was destroyed in a storm about 1865, a new stone courthouse was built there in 1873. In the 1880s, as the San Antonio and Aransas Pass Railroad planned a route from San Antonio to the coast, Helena's citizens did not donate land or raise enough cash for the railroad, while W.G. Butler donated land west of Helena through what is now Karnes City. The railroad therefore bypassed Helena and built its line through Karnes County in 1886-87. Karnes City, established in 1891, had surpassed Helena in population and political clout by 1893, and it was chosen as the new county seat on December 21, 1893. County officials let bids for a new courthouse and jail on January 4, 1894, received bids from Alfred Giles and J. Riely Gordon, and awarded the courthouse contract to John Cormack, who also built courthouses in Concho, Somervell, and Uvalde counties. Cormack died before finishing the structure, and his business associate J.A. Austin completed the job. The courthouse was dedicated on October 25, 1894, and completed on May 29, 1895. The three-story brick building with rusticated stone trim featured Second Empire and Richardsonian Romanesque elements, including projected mansard towers, cylindrical corner towers, and a central clock tower. Alterations beginning in the 1920s added two west-side additions, removed the original clock tower and the conical roofs of the corner turrets, covered the brick with stucco, and blocked off the south entrance. Construction beginning in 2011 and completed in 2018 restored the courthouse to its original 1894 appearance.