This is a spontoon tomahawk not the longer European polearm.
My direct knowledge of these is somewhat limited, and my source materials are not at hand unfortunately. These were almost exclusively trade items meant for Native Americans during the fur trade years, but they were styled after the pole arms used by European armies in the 18th century. Unlike other axes, these were pretty much purely for killing other human beings or ceremonies. This style of head obviously does not lend itself to working wood or other tasks, but it could easily tear through flesh.
The tear drop eye and relatively simple design I believe suggests it is one of the earlier 18th or early 19th century axes traded in the eastern half of the U.S. I've handled a few later pieces made for the western trade, and they generally had round eyes and more ornamental designs.
Again, just what I can recall.
Fixed typos*
