Most population estimates for Maya sites are for the Late Classic period, a time of peak population in the Central Maya Lowlands. At Naachtun, Guatemala, a major city during the Early Classic that continued into the Late Classic period, researchers recently carried out an ambitious program of test pitting in residential areas; its aim was to model the growth of residential units during the entire Classic period and so better contextualize the rise of Classic Maya dynasties and the scale of their economic and political power. This article presents an improvement to the existing method for estimating population for periods preceding the population apex (in this case, the Early Classic period): it not only estimates the occupancy rate of residential units occupied pre-apex but also assesses their size, using a typology I developed based on their morphology and pattern of transformation.