It is separated from northeast Thailand ( Isan ) by the Phetchabun mountain range .
Central Thailand ( central plain ) is a region of Thailand , covering the broad alluvial plain of the Chao Phraya River .
Central Thailand is separated from northeast Thailand ( Isan ) by the Phetchabun mountain range .
Central Thailand ( central plain ) is a region of Thailand , covering the broad alluvial plain of the Chao Phraya River .