Can rank those I have seen only:
Gettysburg
Sharpsburg
Andersonville (battle for life)
Fredericksburg
Vicksburg
Kennesaw Mountain
For a skirmish, Forked Deer River near Humboldt TN
And I would not include Harpers Ferry.
And if you include other sites
National CW Museum
National Museum of Civil War Medicine
Battle of Little Rock
Gettysburg
Sharpsburg
Andersonville (battle for life)
Fredericksburg
Vicksburg
Kennesaw Mountain
For a skirmish, Forked Deer River near Humboldt TN
And I would not include Harpers Ferry.
And if you include other sites
National CW Museum
National Museum of Civil War Medicine
Battle of Little Rock