The excavations at Co Loa have produced several important findings. Perhaps most importantly is some support for the Vietnamese oral histories. Although the findings do not speak to any specific historical or semi-historical events or individuals, they do strongly suggest that a politically centralized, state-level society existed in this area and was responsible for the construction of this site. The evidence also shows that this society was present well before Han colonization. The material evidence also provides support for the occurrence of intra-regional competition and warfare in the Red River valley during the mid first millennium BC. Overall, it would appear that a number of factors, including growing population levels, long-distance trade, metallurgy, intensive farming, and warfare, likely contributed to the emergence of social complexity.
The sheer size and scale of Co Loa and its monumental fortifications strongly suggest a high degree of political centralization was necessary to plan construction and mobilize the requisite resources. Prior to Co Loa, the region’s communities were likely already accustomed to constructing communal works, although likely at a smaller scale (e.g. ditches, dikes, walkways). However, nothing on the scale of Co Loa had ever been attempted before, and the labor necessary for its construction must have required a strong military force and significant centralized, state-like control. Furthermore, the labor requirements strongly imply a high population density. A large population would have been sustainable due to the significant rice paddy agricultural potential of the Red River valley region, which today produces several crop yields annually.
Despite the evidence of continuous, cultural development during the late Neolithic and early Metal Age,the communities in and around Co Loa did not live in a vacuum. Multi-directional interaction was occurring between the Red River Valley communities and counterparts to the north, west, and south before and during the Dongson period. For instance, there are signs of Chinese influence or emulation in some of the cultural elements found at Co Loa, including the stamped earth technique, bronze crossbow bolts, and roof tiles. Bronze drums of the Dongson Culture have been found scattered throughout both mainland and insular Southeast Asia. Future research would be well served by continuing to explore the impact of the powerful Chinese states to the north on Bac Bo societies, even before the latter came to be fully colonized by the Han, as well as interaction with neighboring societies throughout Southeast Asia.
The Co Loa case can also provide insights about the nature of monumentality, early forms of urbanism, and emergent statehood in Southeast Asia. Many researchers recognize the significance of the historic and classical states of the first and second millennia AD, such as Angkor and Champa. However, earlier societies from the first millennium BC can help augment our understanding of sociopolitical trajectories and factors that led to social complexity. Co Loa’s system of enclosures and moats are to some extent foreshadowed by hundreds of moated settlements scattered throughout Southeast Asia during the first millennium BC. Perhaps the largest in this category of Iron Age settlements, Co Loa site is emblematic of a tradition of settlements marked by earthworks and moat systems, one that would see the emergence of large hydraulic cities such as Angkor centuries later. Dating to the closing centuries BC, Co Loa represents one of the earlier cases of ancient state-level societies seen in Vietnam and in the wider Southeast Asian region.