▁( OM B ) ▁has ▁defined ▁ 9 1 7 ▁core - based ▁statistical ▁areas ▁( C BS As ) ▁for ▁the ▁United ▁States ▁and ▁ 1 2 ▁for ▁Puerto ▁Rico . ▁ ▁The ▁O MB ▁defines ▁a ▁core - based ▁statistical ▁area ▁as ▁one ▁or ▁more ▁adjacent ▁count ies ▁or ▁county ▁equival ents ▁that ▁have ▁at ▁least ▁one ▁urban ▁core ▁area ▁of ▁at ▁least ▁ 1 0 , 0 0 0 ▁population , ▁plus ▁adjacent ▁territory ▁that ▁has ▁a ▁high ▁degree ▁of ▁social ▁and ▁economic ▁integration ▁with ▁the ▁core ▁as ▁measured ▁by ▁comm uting ▁t ies . ▁ ▁The ▁ 9 2 9 ▁Core ▁Based ▁Statist ical ▁Are as ▁currently ▁defined ▁by ▁the ▁O MB ▁include ▁the ▁ 3 8 8 ▁metropol itan ▁statistical ▁areas ▁( MS As ), ▁which ▁have ▁an ▁urban ▁core ▁population ▁of ▁at ▁least ▁ 5 0 , 0 0 0 , ▁and ▁the ▁ 5 4 1 ▁Mic ropol itan ▁statistical ▁areas ▁( μ S As ), ▁which ▁have ▁an ▁urban ▁core ▁population ▁of ▁at ▁least ▁ 1 0 , 0 0 0 ▁but ▁less ▁than ▁ 5 0 , 0 0 0 . ▁__ TO C __ ▁ ▁United ▁States ▁ ▁The ▁following ▁sort able ▁table ▁lists ▁the ▁ 9 1 7 ▁core - based ▁statistical ▁areas ▁( C BS As ) ▁of ▁the ▁United ▁States ▁with ▁the ▁following ▁information : ▁ ▁The ▁C B SA ▁rank ▁by ▁population ▁as ▁of ▁July ▁ 1 , ▁ 2 0 1 2 , ▁as ▁estimated ▁by ▁the ▁United