A maidam is a tumulus of the royalty and aristocracy of the medieval Ahom Kingdom in Assam, India. The royal maidams are found exclusively at Charaideo, near Sibasagar; whereas other maidams are found scattered in the region between Jorhat and Dibrugarh towns. Structurally, a maidam consists of vaults with one or more chambers. The vaults have a domical superstructure that is covered by a hemispherical earthen mound that rises high above the ground with an open pavilion at the peak called chow chali. An octagonal dwarf wall encloses the entire maidam.
The structural construction and the process of royal burials are explained in historical documents called Chang-Rung Phukanor Buranji, which detail even the articles that were buried. Later excavations under the Archaeological Survey of India found some of the maidams previously defiled, with the articles mentioned in the Buranji missing. Many of the maidams were excavated and looted, most famously under the Mughal general Mir Jumla who had occupied Garhgaon briefly in the 17th century, and under the British after 1826.
The Ahom community in Assam consider the excavation as an affront to their tradition, because the maidams are associated with the Ahom ancestor worship and the festival of Me-Dam-Me-Phi.