Missouri passed constitutional carry last year or the year before. Quite a few states do this now. IIRC, New Hampshire was the one about 10 years or so ago.

If you are legal to own a gun, you are legal to carry it. Some of the states may have restrictions or open vs. concealed though. I didn't look them all up.

U.S. jurisdictions that have constitutional carry
Alaska
Arizona
Arkansas[disputed]
Idaho (residents only)
Kansas
Maine
Mississippi
Missouri
New Hampshire
North Dakota (residents only; concealed carry only)
Vermont
West Virginia
Wyoming (residents only)

U.S. States that have a limited form of permitless concealed carry
Montana (outside city limits)
New Mexico (unloaded weapon & loaded magazine, vehicle carry)
Oklahoma (residents of constitutional carry states)