Whilst at first glance you might think this is a US Civil War bayonet a close look at the scabbard throat reveals the date of 1886 which is the year that the US Indian wars ended when on September 4, 1886 - At Fort Bowie in southeastern Arizona, Geronimo and his band of Apaches surrender to Brigadier General Nelson A. Miles. This signaled the end of warfare between the United States Army and Indian tribes.
This bayonet comes with its original metal scabbard and is in good condition for its age. The brass frog button is clearly marked NGP which has two possibilities one being National Guard Pennsylvania or the other being National Guard Philadelphia.