American Bowie knife?

[not2sharp]

Also, the knife probably had a makers mark once. But, it has been lost to surface corrosion. The panel below, which is a closeup of possible mark extending only 1/2” was perhaps part of a larger more elaborate stamping.

N2s

This is a closeup of the blade show at the bottom of post 1. The mark can be seen about 2-1/2” in front of guard, near the center and parallel with the blade.