war axe

i believe this is a war axe, found it after the field was plowed. Its 71/4 inches long 4 inches tall 2 5/8 thick with a 7/8 grove not sure of the weight but pretty heavy .There is only one nick on and its on the other side and it 1 inch by 1/2 other than that its very clean. even the sharp end is still sharp. I am not sure but on the back edge it has what i wood call a fluted groove running down the entire length of it.so if there is any one could help me with a time era or tribe this might of come from i would sure would appreciate it .and this was found in northern missouri.