The population of Tikal began a continuous curve of growth starting in the Preclassic Period ( approximately 2000 BC – AD 200 ) , with a peak in the Late Classic with the population growing rapidly from AD 700 through to 830 , followed by a sharp decline . For the 120 square kilometres ( 46 sq mi ) area falling within the earthwork defenses of the hinterland , the peak population is estimated at 517 per square kilometer ( 1340 per square mile ) . In an area within a 12 kilometres ( 7 @.@ 5 mi ) radius of the site core , peak population is estimated at 120 @,@ 000 ; population density is estimated at 265 per square kilometer ( 689 per square mile ) . In a region within a 25 kilometres ( 16 mi ) radius of the site core and including some satellite sites , peak population is estimated at 425 @,@ 000 with a density of 216 per square kilometer ( 515 per square mile ) . These population figures are even more impressive because of the extensive swamplands that were unsuitable for habitation or agriculture . However , some archaeologists , such as David Webster , believe these figures to be far too high .