Concealed carry is carrying a weapon such as a handgun in a concealed manner, either on one's person or nearby.
Most states banned it in the 19th century as the practice of criminals, whereas open carrying was seen as legitimate for self-defence.
A special permit was required for concealed carry, with only certain qualified people granted a license.
The exception was Vermont, which never had any restriction.
Recently, other states such as Alaska, Arizona, Kansas, New Hampshire and Maine have changed the law to allow unrestricted concealed carry by eligible residents.
Others states have partial restrictions or require a permit.
Some areas can be declared "gun free zones", allowing businesses put up a sign that makes it is illegal to carry a concealed firearm on the premises.
As of 2017 there had been 16.3million concealed weapon permits issued in the United States.