Its probably a Napoleonic period French musket. Tens of thousands of them were imported after 1815. Since you are apparently new to this...under US law every male citizen from the ages to 18 to (I think) 45 was required to have a musket suitable for militia service. When the Napoleonic wars ended and Europe was awash with surplus arms literally shiploads of French and French-style muskets were imported to satisfy that demand.