While Los Guachimontones was founded in the Late Formative period, there is some evidence of a Middle Formative occupation suggesting some temporal continuity at the site. Major construction began in the Late Formative and continued into the Early Classic. Monumental construction appears to have tapered off in the Late Classic with a decline in population followed by a drastic decline in the Epiclassic. Population levels rebounded to their Early Classic levels in the Postclassic, but with no monumental construction at or near the site.