Arroyo de Piedra occupies a strategic position between the sites of Dos Pilas and Tamarindito, the dominant polities in the Petexbatun region. Temples, palaces, sculptured monuments, quarries, and a defensive wall reflect the importance of this small site. Archaeological and epigraphic investigations conducted by Vanderbilt University from 1990 to 1994 demonstrate that Arroyo de Piedra was founded and ruled by members of the royal family of Tamarindito during the Early Classic. In the Late Classic, Arroyo de Piedra was absorbed by the expansionistic Dos Pilas dynasty through a matrimonial alliance. The marriage was apparently imposed by means of coercion as suggested by evidence of intentional destruction of local sculpture. The center was abandoned during the Terminal Classic, after the fall of Dos Pilas.

The archaeological site of Tamarindito is located on an elevated escarpment that gives it a wide panoramic view of various distances all around, especially toward the northeast in the direction of the Río Petexbatun and the lake with the same name, in addition to the well-known, important archaeological site of Seibal. Tamarindito is 7 km east of Dos Pilas and 7 km northwest of Aguateca. It is one of the most important sites of the Petexbatun region and the capital of the most ancient polity of the region.

Archaeological investigations at Aguateca, Guatemala, by the Petexbatun Regional Archaeological Project have provided clues to the intriguing sequence of the downfall of this Maya center. The earliest substantial occupation at Aguateca dates to the Late Preclassic period. After very little presence during the Early Classic period, Aguateca rapidly grew into a densely occupied center, probably at the beginning of the eighth century a.d. Migration from other areas may have contributed to this rapid population growth. In the late eighth century, extensive defensive walls were constructed, most likely as a response to intensified warfare. Despite this defensive effort, Aguateca was finally attacked and brought down by enemies probably at the beginning of the ninth century. The center appears to have been almost completely abandoned soon after this event. This reconstructed sequence confirms other evidence of the Petexbatun Project that intensified warfare played an important role in the Classic Maya collapse.

The Petexbatun Regional Cave Survey (PRCS) is the first large cave study to be undertaken as part of a major archaeological expedition. The survey's primary objective was assessing the extent to which surface architecture at Dos Pilas was configured by features in the sacred landscape. All three of the major architectural complexes at the site had a direct relation to caves, and a number of important secondary buildings and even residential units were deliberately laid out to incorporate caves. Excavation revealed evidence of Preclassic utilization of all of the major caves, indicating that their status as sacred landmarks had been established long before the eighth century florescence of the site. The importance of the caves in site configuration was mirrored in the artifact assemblage. Despite the survey's much smaller size, the cave investigations recovered 20–50% more of the overall assemblage at Dos Pilas in an array of artifact categories. A review of the archaeological literature suggests that the importance ascribed to caves at Dos Pilas in both site configuration and local economy can be found elsewhere and probably reflects a much wider pattern of utilization.