All 50 states and DC allow the concealed carry of firearms. Ten states allow concealed carry without a permit, eight states have some discretion in approving permit applications, and the rest issue permits to all applicants who meet the requirements.
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All 50 states and DC allow the concealed carry of firearms. Ten states allow concealed carry without a permit, eight states have some discretion in approving permit applications, and the rest issue permits to all applicants who meet the requirements. 

 (via State-by-State Concealed Carry Permit Laws - Concealed Guns - ProCon.org)

Source: concealedguns.procon.org