Construction histories of ancient Maya monumental centers have long been used to interpret the growth and decline of Lowland Maya polities. Changes in the built environment at monumental centers reflect labor appropriation by ruling elites and may indirectly serve to gauge changes in political clout over time. Consequently, the precision and accuracy with which archaeologists measure these changes take on increased importance when assessing the ancient Maya political landscape. Recent excavations in the monumental core of La Milpa, Belize, have generated new data that call for a re-assessment of the center's historical trajectory. Our data indicate that La Milpa had a larger Late Preclassic foundation, likely grew much more incrementally through the Classic period, and persisted centuries longer than previously understood. The apparent persistence of occupation into the tenth century a.d. challenges the traditionally accepted dates for La Milpa's abandonment, and, the ceramic sequence upon which it is often based.