Holtun, originally named La Máquina, is a Maya archaeological site located in the Petén Department of northern Guatemala on the road to Melchor de Mencos from Flores. The city had a long period of occupation that lasted from the Middle Preclassic through to the Late Classic periods. The site was officially recognized by the Guatemalan authorities in 1994 in response to reports from the local community of looting activity in the area. This looting had revealed large masks sculpted onto the side of one of the principal structures at the site. Holtun is the southernmost site in the Maya lowlands that is known to have such masks. The site is characterized by the presence of two particular architectural groups, consisting in a triadic acropolis and an E Group, which are markers of the sociocultural complexity of the Preclassic period in the Lowland Maya area. In addition, the nature of the karstic bedrock allowed for the creation of a great quantity of chultuns, which can be found in almost all of the architectural groups

The site was originally named as La Maquina after the nearest village but was renamed as Holtun by Agustín Estrada Monroy, the then director general of the Patrimonio General Cultural y Natural (General Cultural and Natural Heritage). The new name is derived from the local Itza Maya language and means "stone head". The land surrounding the site has been completely deforested and is used for the cultivation of maize, beans and plantain, with ownership divided among the municipality and private landowners .

The ruins of Holtun are located among a cluster of important Classic Period cities. Tikal is located 35 kilometres (22 mi) to the northwest, Yaxha is 12.3 kilometres (7.6 mi) to the north and Naranjo is 25 kilometres (16 mi) in the same direction.

The site is located 1.3 kilometres (0.81 mi) to the south of La Maquina village, in the municipality of Flores. Holtun lies in a broken hilly region upon a karst ridge running from northeast to southwest. It is situated on a hilltop at an altitude of 300 metres (980 ft) above mean sea level and is bordered on the south, east and west sides by three seasonal streams. There are no rivers passing very close to the site due to the local topography, with those watercourses to the south of the city draining toward lake Camalote some 3 kilometres (1.9 mi) to the south. The Mopan and Salsipuedes rivers flow 3 kilometres (1.9 mi) to the east of the lake, and the La Blanca lake is situated 8 kilometres (5.0 mi) further south. The watercourses to the north of the ruins flow northward towards Laguna Yaxhá.

The site was occupied from the Middle Preclassic period right through to the Late Classic period.

The archaeological evidence obtained from looters trenches and systematic excavations in the E-Group suggests that Holtun plateau was occupied during the Early Preclassic period. The ceramics obtained from the context include potsherds from Mamon horizon. The excavations at the Triadic Acropolis reveals an occupation around the Late Preclassicperiod, associated with the Chicanelhorizon. The Early Classic period occupation in Holtun was identified in the elite residential groups, particularly in the groups C, D, E and F. The Late Classic period was associated with architecture modifications for residential purposes. The ceramic evidence for the Terminal Classicperiod is minimum and comes from sectors associated with the main plaza near the Group C.

Holtun was officially discovered in February 1994, when the Guatemalan Instituto de Antropología e Historia (IDAEH - "Institute of Anthropology and History") was notified of the looting of a previously unknown site between Flores and Melchor de Mencos. IDAEH investigators are estimated to have arrived at the site between six and eight months after looting had started, during which time the major architecture at the site had been damaged. The site was thoroughly surveyed by IDAEH's Department of Prehispanic and Colonial Monuments (Departamento de Monumentos Prehispánicos y Coloniales) in June and July 1994. New archaeological investigations were initiated in 2010 by Brigitte Kovacevich and Michael Callaghan of Southern Methodist University.

The first official reconnaissance of the site was performed in 1994 by Erick Ponciano and the first map of the site was created. In 1998 and 2001 respectively, two field seasons were performed looking for rescuing information from the previous looting practices. The result was a valuable documentation of the site and its archaeological traits, particularly the masks at the building facades and the Chultuns. The seasons were performed by personnel of Yaxhá project from the National Institute of Anthropology and History of Guatemala, and conducted by Vilma Fialko. In 2010 the first season of Holtun Archaeological Project, with the support of Southern Methodist University, perform the first field season. During this season, personnel of the project did an exhaustive reconnaissance and surveying, creating a new map of the site. During the 2011 season, the project perform test pits in the plazas with the objective of collecting information to understand the ceramic sequence of the site. Also, the excavations pursued to understand the settlement pattern through the study of architectonic modifications in the plazas. The season of 2012 consisted in the analysis of materials collected during the previous season, particularly ceramics, Obsidian and carbon samples for Radiocarbon dating. During the next season in 2014, new test pits were done and the mapping project incorporates new land segments and archaeological traits. During this season, soil samples were taken to understand the chemical composition of the floors at the plazas through X-ray fluorescence analysis.