Cai Hou Ancestral Hall is situated beside Caizi Lake in the southeast urban area of Leiyang City, Hunan Province. It was designated as one of the Sixth Batch of Major Historical and Cultural Sites Protected at the National Level by the State Council.

   According to legend, the site was the former residence of Cai Lun, the inventor of papermaking and Cai Lun paper in ancient China. During the reign of Emperor He of the Eastern Han Dynasty, Cai Lun served as Shangfang Ling, the official in charge of manufacturing imperial artifacts. He summarized the papermaking techniques developed since the Western Han Dynasty, and made paper using waste fishing nets, rags, hemp remnants and other raw materials. In the first year of the Yuanxing reign (105 AD), he presented his invention to Emperor He. Later generations built an ancestral hall on the original residence site in his memory.

    The exact original construction date is unrecorded. It was rebuilt in the fourth year of the Zhiyuan reign of the Yuan Dynasty (1338) by Chen Zongyi, the prefectural governor. Having undergone multiple rises and falls through history, the existing ancestral hall is a Qing Dynasty building, renovated in 1956 and 1981 respectively. It is a three-yard courtyard-style single-storey brick-and-wood structure with grey tiled roofs.