▁the ▁ 2 0 th ▁century , ▁most ▁of ▁the ▁educational ▁institutions ▁here ▁were ▁established . ▁In ▁ 1 9 5 1 , ▁the ▁village ▁gained ▁town ▁status ▁and ▁in ▁ 1 9 8 7 , ▁it ▁was ▁declared ▁a ▁city . ▁ ▁Government ▁As ▁a ▁municipality , ▁the ▁city ▁of ▁At la com ul co ▁is ▁the ▁local ▁government ▁for ▁nearly ▁ 1 1 0 ▁other ▁communities ▁in ▁the ▁area , ▁which ▁cover ▁a ▁territory ▁of ▁ 2 5 8 . 7 4 km 2 . ▁ ▁Only ▁about ▁a ▁quarter ▁of ▁the ▁municipality ' s ▁population ▁of ▁ 7 7 , 8 3 1 ▁lives ▁in ▁the ▁city ▁proper . ▁▁ ▁The ▁ ▁municipality ▁has ▁a ▁large ▁percentage ▁of ▁ind igen ous ▁pe op les ▁for ▁central ▁Mexico , ▁at ▁ 2 0 %, ▁compared ▁to ▁ 3 . 8 ▁percent ▁for ▁the ▁rest ▁of ▁the ▁State ▁of ▁Mexico , ▁with ▁ 8 , 8 2 0 ▁people ▁speaking ▁a ▁native ▁language ▁, ▁with ▁Maz ah ua ▁domin ating . ▁The ▁municipality ▁borders ▁the ▁municipal ities ▁of ▁Ac amb ay , ▁Tem as cal cing o , ▁San ▁And rés ▁Tim il pan , ▁San ▁Bart olo ▁Mor el os ▁and ▁El ▁O ro . ▁ ▁The ▁municipality ▁has ▁rug ged ▁terrain , ▁filled ▁with ▁mountains ▁and ▁hills . ▁ ▁It ▁is ▁located ▁on ▁the ▁Trans - M ex ican ▁Vol can ic ▁B elt , ▁in ▁the ▁L akes ▁and ▁Vol can os ▁of ▁An á hu ac ▁region .