▁Z ula , ▁the ▁Ver de ▁River , ▁the ▁J uch ip ila ▁and ▁the ▁B ola ños . ▁About ▁three ▁qu arters ▁of ▁the ▁state ' s ▁population ▁lives ▁near ▁this ▁river ▁system . ▁In ▁the ▁south west ▁of ▁the ▁state , ▁there ▁are ▁a ▁number ▁of ▁small ▁rivers ▁that ▁empty ▁directly ▁into ▁the ▁Pacific ▁Ocean . ▁The ▁most ▁important ▁of ▁these ▁is ▁the ▁Am eca , ▁with ▁its ▁one ▁main ▁trib ut ary , ▁the ▁M asc ota ▁River . ▁This ▁river ▁forms ▁the ▁state ' s ▁border ▁with ▁N ay ar it ▁and ▁em pt ies ▁into ▁the ▁I p ala ▁Bay . ▁The ▁Tom at lán , ▁San ▁Nicol ás , ▁Pur ificación , ▁Mar ab as co - Min at it lán , ▁Ay u qu ila , ▁T ux c ac ues co , ▁Ar mer ía ▁and ▁T ux pan ▁rivers ▁flow ▁almost ▁per pend icular ▁to ▁the ▁Pacific ▁Ocean ▁and ▁d rain ▁the ▁coast al ▁area . ▁Another ▁river ▁of ▁this ▁group ▁is ▁the ▁C ih u at lán ▁River , ▁which ▁forms ▁the ▁boundary ▁between ▁J alis co ▁and ▁Col ima ▁empty ing ▁into ▁the ▁Bar ra ▁de ▁Nav idad ▁Bay . ▁ ▁The ▁sout he astern ▁corner ▁belongs ▁to ▁the ▁B als as ▁River ▁bas in . ▁This ▁includes ▁the ▁Ay u q ila ▁and ▁T ux c ac ues co , ▁which ▁join ▁to ▁form ▁the ▁Ar mer ía ▁and ▁the ▁T ux pan . ▁ ▁The ▁other ▁main ▁surface ▁water ▁is