Lavaca County's courthouse is the fifth structure to serve as its seat of justice. Lavaca was created originally as "La Baca," a judicial county, by the Congress of the Republic of Texas in 1842, then, after judicial counties were declared unconstitutional, it was created anew by the First Legislature of the State of Texas on April 6, 1846, and organized on July 13, 1846. The earliest courthouse was built of logs, and after that building burned, court was held for a time under a liveoak tree in the old town of Petersburg. Since the county seat was moved to Hallettsville in 1852, this has been the third courthouse on this site. Richardsonian in style, the building is made of Mineral Wells brown sandstone with a base and trim of Mills County grey stone. Eugene T. Heiner of Houston, known for his public buildings, was the architect, and contractors A. T. Lucas and C. H. and J. Stadtler erected the structure in 1897-1899. The county dedicated the building on July 4, 1899, led by members of the Hallettsville Schuetzen Verein, Silver Cornet Band, Fire Department, Sons of Hermann, and other orders, with Judge P. H. Green delivering the main address. The courthouse square was selected by the Texas Society of Architects in 1970 for a restoration study, and the courthouse was placed on the National Register of Historic Places in 1971.