The Macon County Courthouse and Annex is a historic courthouse and annex located at Courthouse Sq. in Macon, Macon County, Missouri. It was built in 1865, and is a two-story, cross-plan, Romanesque Revival style brick building with Italianate style detailing. It sits on a limestone foundation and has a gross-gable roof. The annex building was constructed in 1895. It is a two-story, T-shaped, building constructed of red brick with limestone, wooden and cast iron trim. It was added to the National Register of Historic Places in 1978.