Tayabas Isthmus, separates the Bicol Peninsula from the main part of Luzon Island, and the Bondoc Peninsula which lies between Tayabas Bay and Ragay Gulf.
References
Tayabas Isthmus Wikipedia(Text) CC BY-SA
Tayabas Isthmus, separates the Bicol Peninsula from the main part of Luzon Island, and the Bondoc Peninsula which lies between Tayabas Bay and Ragay Gulf.