Editing Overview of gun laws by nation (section)

===United States===
{{Main|Gun law in the United States|Gun laws in the United States by state|Concealed carry in the United States|Open carry in the United States}}
{{Concealed carry permit requirements in the US}}
{{More citations needed section|date=April 2024}}
[[File:Open Carrying US states map.svg|thumb|A map of [[Open carry in the United States|open carry laws]] in the United States:
{{legend|#008000|Legal with no permit/license required}}
{{legend|#00cd00|Legal with no permit/license required; possible local restrictions}} <!-- they should be updated for 2023 to reflect the fact that Florida also has constitutional carry also known as the ability to carry without any special permit -->
{{legend|#ffff00|Legal with permit/license}}
{{legend|#FF0000|Illegal}}]]
In the United States, firearms are regulated by both federal and individual state statutes. Federal firearms laws are enforced by the [[Bureau of Alcohol, Tobacco, Firearms and Explosives]] (ATF). State and local firearms laws, which vary greatly, are enforced by state and local authorities. The [[Right to keep and bear arms in the United States|right to keep and bear arms]] has been protected by the [[Second Amendment to the United States Constitution|Second Amendment]] to the Constitution since 1791,<ref>{{cite web|url=https://www.archives.gov/exhibits/charters/bill_of_rights.html|title=America's Founding Documents|date=30 October 2015}}</ref> and the [[United States Supreme Court|U.S. Supreme Court]] ruled that it protects any individual's right to keep and bear arms unconnected with service in a militia for traditionally lawful purposes, such as self-defense within the home and in public, in ''[[District of Columbia v. Heller]]'' (2008) and ''[[New York State Rifle & Pistol Association, Inc. v. Bruen]]'' (2022). The Supreme Court affirmed in ''[[McDonald v. City of Chicago]]'' (2010) that the Second Amendment is [[Incorporation of the Bill of Rights|incorporated]] by the [[Due Process Clause]] of the [[Fourteenth Amendment to the United States Constitution|Fourteenth Amendment]] and thereby applies to state and local laws as well as federal laws. Most state constitutions also guarantee this right, although there is some variance across the country as both federal and state laws apply to firearm possession and ownership.

Firearm ownership in the United States is by right and does not require licensure or proof of need. Federally, there is a minimum age of 18 to possess a handgun, with no minimum age for long guns.<ref name="juvenile-possession">{{UnitedStatesCodeSub|18|922|x|2}}</ref> To purchase from a licensed dealer, one must be 18 for long guns and 21 for handguns.<ref name="dealer-min-age">{{UnitedStatesCodeSub|18|922|b|1}}</ref> The respective age requirements apply to purchasing ammunition from a dealer, retail store or online.

Federally, new firearms must be transferred by a federally licensed dealer (FFL) with form 4473 and background check. Used firearms transferred interstate must also go through an FFL. Intrastate private party sales are not required to use an FFL under federal law, but many states require FFLs to conduct private party transfers.

Federal law does not limit the number of firearms or quantity of ammunition and reloading supplies a private citizen may keep.

Air guns, antique ignition (muzzle loading) guns and guns made prior to 1899 are not firearms under U.S. law, although they are still considered deadly weapons.

Federal law designates two classes of firearms in the United States:

Title I, GCA firearms: This includes all handguns, rifles with at least 16" barrel and 26" overall length, Shotguns with at least 18" barrel and 26" overall length, other firearms with an overall length of 26" or more which are neither handgun nor long gun. Sporting arms over .50 caliber are title I; non-sporting arms over .50 caliber fall into the Title II category below.

Title II, NFA Firearms. NFA firearms include:

* Machine guns (fully automatic firearms; those that can fire more than one shot by a single function of the trigger)
* Short Barreled Rifles (<16" rifled barrel or <26" OAL)
* Short Barreled Shotguns(<18" smoothbore barrel or <26" OAL)
* Destructive Devices (Non-sporting weapons over .50 caliber, anything with more than 1/4 ounce explosives content)
* Any Other Weapon (generally, firearms which do not look like firearms or which would be a smoothbore "other firearm" except that its overall length is too short)
* Silencers (suppressors; any device designed or redesigned and intended to reduce the report of a gunshot). Sound suppressors which are permanently attached to a non-firearm (e.g. air rifle, muzzle-loader) are not considered firearm silencers and are not regulated.

Non-prohibited persons over 21 years of age may own NFA firearms in most states, though some states prohibit some or all of this class. NFA firearms must be registered and go through a manufacturing or transfer approval by ATF before the individual may make or take possession of the weapon. This process can take months, sometimes even years. It requires fingerprinting, photo ID and a tax of $200 per application (per weapon). 

Fully-automatic firearms (machine guns) are heavily restricted and can only be owned by private citizens if manufactured and registered before 18 May 1986. unless an individual is to obtain status as an SOT "Special Occupational Taxpayer" as a FFL "Federal Firearms License" holder. Since civilians without SOT status are only allowed to own machine guns manufactured before 1986, the finite supply has caused the market value of pre-1986 transferable automatic weapons to be 20 to 50 times that of their semiautomatic counterparts (2022 ex.,$500–$800 for a basic AR-15, $20,000-$25,000 for an M-16)<ref>{{Cite web|url=https://rocketffl.com/who-can-own-a-full-auto-machine-gun/|title=Who Can Own a Full-Auto Machine Gun?|date=2 January 2021|website=RocketFFL}}</ref>

Law varies greatly from state to state, both in its scope and in its range.<ref>{{Cite web|url=http://www.theguardian.com/world/us-news-blog/2013/jan/16/gun-laws-need-to-know|title=Gun laws in the US: seven things you need to know about the data|date=16 January 2013|website=The Guardian}}</ref>

Pursuant to {{UnitedStatesCode|18|922}} – Unlawful Acts, persons are prohibited from possessing firearms or ammunition if:<ref>{{cite web |url=https://www.atf.gov/files/forms/download/atf-f-4473-1.pdf |title=Firearms Transaction Record |website=www.atf.gov |archive-url=https://web.archive.org/web/20150215165624/https://www.atf.gov/files/forms/download/atf-f-4473-1.pdf |archive-date=15 February 2015}}</ref>
* They have been convicted of a felony, or any other crime for which they could have been sentenced to more than a year in prison, or are under indictment for such
* They are a fugitive from justice
* They have been convicted of a misdemeanor crime of domestic violence
* They are an unlawful user of, or addicted to, any illegal controlled substance
* They have been adjudicated mentally defective
* They have been discharged from the Armed Forces under dishonorable conditions
* They have renounced their United States citizenship

The carrying of weapons, either [[Open carry in the United States|openly]] or [[Concealed carry in the United States|concealed]], is regulated by the states, and these laws have changed rapidly beginning in the latter part of the 20th century. Some states allow residents to carry [[Constitutional carry|without a permit]], while others only allow the public carry of firearms upon issuance of a permit or license. Under the [[Law Enforcement Officers Safety Act]], current and former law enforcement officers can carry anywhere (except private property where they are subject to the rules of the owner and gun-free public places like schools) as long as they carry a photo identification from their agency and have completed yearly training from said agency.

Federal law provides protection for travellers who may find themselves going through states with more restrictive gun laws than their origin or destination. As long as the weapons are transported in accordance with [[FOPA]] and the weapon(s) are legally owned and not prohibited in the origin or destination(s), the travellers are immune from prosecution.

Being engaged in the business of importing firearms, dealing firearms, gunsmithing or manufacturing arms requires licensure in the United States. There are multiple license types, depending on the nature of the business, and some licenses have additional requirements, such as registration with Directorate of Defense Trade Controls.

Private citizens in the United States may manufacture weapons for personal use without government approval or registration for Title I GCA firearms (NFA rules still apply to home made weapons). It becomes unlawful to manufacture without a license if the intent is to distribute.

The United States federal government is prohibited by law from maintaining a registry of firearms owners, although the NFA registry which predated this prohibition has been exempted. Some states do have registration.