As of 22 February 2017, Alaska, Arizona, Arkansas[disputed], Idaho (residents only),
Kansas, Maine, Mississippi, Missouri, New Hampshire, Vermont, West Virginia[5] and
Wyoming (residents only) do not require a permit to carry a loaded concealed firearm for
any person of age who is not prohibited from owning a firearm. Permitless carry
in Idaho and Wyoming is applicable to residents only; non-residents must have a
permit to carry a concealed handgun in these states. All aforementioned jurisdictions
do not require a permit to openly carry either except for certain localities in Missouri.
https://en.wikipedia.org/wiki/Constitutional_carry
‘Of age’ in Vermont could mean as young as ten years old.