Pretty much a Kentucky pattern, with long poll and similar length bit. It could go back to the 1700s or have been forged last week. It does appear to have a welded on hard hammer poll, which I've seen on older axes. Assuming the bit is formed with steel inserted into the wrought iron body of the axe? If wrought iron, I'd guess pre-1900, but just a guess. The profile is similar to a couple of colonial era finds I've seen posted online. I'll look up the link if it will help.
