UPDATE 2012 & 2014:
The following articles about the Bago were submitted by Ferdinand Ammang Anno. They provide an interesting insight into the history of the Bago and its culture:
Of Sintatako, Tongtongan, Begnas and Papatayan Toward an indigenous spirituality for the struggle: A Bago Perspective by Ferdinand Ammang Anno
There is a an extensive essay on the Bago (site has expired) found on the internet by Mr. Vic Buaquen who delivered the speech at the the Third Bago Congress in San Emilio, Ilocos Sur on April 23, 2003.
Many of the residents of Sagunto and the surrounding barangays are descendants of The Bago. The Bago tribe is, after some controversy (read Mr. Buaquen’s essay), confirmed as one of the indiginous peoples of the Philippines by the National Commission for Indigenous Peoples (NCIP).
Mr. Buaquen defines the Bago as:
…the most reliable definition of the Bago is what we Bagos know ourselves to be and not the definition of historians, academicians and scholars. The simple fact that many of us are still clamoring for a definition of the Bago should clearly show that historians, academicians and scholars have failed us in this regard. The only acceptable definition of the Bago today is self-ascription of the Bagos themselves. While we are aware of our identity as far as we can remember and now having a legal basis for its confirmation in the IPRA, we still seem to want it formally laid down. And I hereby propose a seed definition for a more comprehensive one that could be done later. This definition is culled from our own deliberations in previous congresses as well as other Bago sources which should be sufficient to distinguish us from all the other ethnic groups and indigenous peoples of the Philippines. And, it is: The Bago are hilltribe dwellers in the border regions between Ilocos and Cordillera mountains who are the offspring of intermarriages as well as product of trade between mountain tribes of the Cordillera and the Iloko of the lowlands. They have evolved their own distinct culture and dialect, which distinguish them from their neighboring tribes and other adjacent ethnic groups.
~ excerpt from The Bago by Mr. Vic Buaquen
Here is an interesting presentation about the Bago found on Prezi:
Bago Trivia on the Web: 2014 update:Many of the previous links on this page have expired, unfortunately, so they have been removed.I will renew the online research and post more resources here as I come across them.
This map, showing the “Igorot Territory”, was borrowed from the Bago National Cultural Society of the Philippines website (website has also expired). According to this site, the greater part of the territory is the home and origin of the bago.