Highland Hall, also known as the Courthouse Annex, is a historic school building located at Hollidaysburg, Blair County, Pennsylvania. It was designed by noted Philadelphia architect Samuel Sloan (1815-1884) and built about 1865. It is a four-story, "T" shaped stone building measuring 150 feet wide and 160 feet deep. It features a mansard roof, characteristic of the Second Empire style. It was originally built to serve as a Presbyterian seminary for both sexes. It became a female academy and officially named Highland Hall in 1911. It continued to be used as a girls' school until 1940. It became a county office building in 1969.