Hi Charles:
I believe that the hilt is Ilokano work in that it is a horse hoof shape with a prominent groove below the "hoof." Ilokano hilts frequently have a notch or groove in this position, where the little finger rests comfortably. It is seen with many of their hilt styles, which are quite numerous and have been described
here previously.
The brass (?) ferrule is also consistent with Ilokano work. The bulge in the grip adjacent to the ferrule is something I associate with Central Luzon/Pampanga (see, for example, many of the Apalit knives that have also been described
here). Putting all that together, I think this was made in the area from Pampanga up to Pangasinan by local crafstmen who were either Ilokano or strongly influenced by Ilokano styles. The same area was responsible for many of the "Negrito" bolos, which can be used to define many of the Ilokano traits in knifemaking (as discussed
here).
Blade forms are varied, with the
tabak (aka the Negrito
katana),
dahong palay, and
ginunting being quite common, as well as clipped blades (some resembling a Bowie knife). There are other styles as well, including heavy-bladed work knives of various forms, and even a "double-clipped" version. I've attached a picture of the latter profile on a large knife that measures 21.5 inches overall.
There are a lot of nice knives coming out of northern Luzon.
Ian.