Kronckew is dead on with his comments. At first glance, it does very much resemble many of the French boarding types, specifically the m1833 hache de borde, but it would be classified as a 'private purchase' if it is such. That means it would have been made in the style of those used by naval forces, but for merchant ships. Likewise, as my colleague pointed out, many of these type axes still exist as fire implements (which was the final evolution of the boarding ax aboard ships) and tool axes used by infantry units, etc. This one does have a few points going for its possible boarding ax classification-
#1. Its a bearded axe blade, meaning the blade edges curve both up and down. This is an old-style type and not typically seen post-1900, when many of the field axes are seen.
#2. The spiked point! If you look at many of the fire axes that evolved from the boarding pieces, their spikes are not of this pattern. This 4-sided point resembles the earlier patterns. At worst, if it is an old fire ax, it truly is OLD!
#3. The long haft. When we see the camp axes, Brit fire pieces, military axes, etc, they all ususally have pretty short hafts. The one pictured looks contemporary with the piece, is very long to allow for a good swing in battle, and has a butt that flares, as seen on some boarding pieces.
#4. The patina. This is not a late 19th/early 20th c. piece, IMO. It looks genuinely old, pre-1850? Fire axes were just evolving back then and no camp axes resembling this sytle back then.
#5. This appears to my weak eyes to be blacksmith-made? Or at least a very early trip-hammer made casting. Even the weak edge to the blade, although making one suspect that it might be ceremonial, could also support a crude boarding weapon, which were contracted weapons with local smiths or one-off patterns that didn't make the cut for naval that firms sold to local merchantmen of the period.
#6. Forward and rear-facing langets to secure the head. Yes, we see these on both boarding and fire pieces, but as far as I know, the English pieces had side to side langets and American boarding axes had none. That would make this either a French or Scandinavian pattern, and I am unaware of any existing fire axes resembling this one from those countries.
My .02 cents.
P.S. Is it for sale???