Gun laws by state sit on top of a federal baseline that applies everywhere in the country. Federal law sets who can buy a firearm, who is barred from possessing one, and how licensed sales work. Everything else — how you carry, whether you need a permit, which firearms and magazines are legal, when you can use deadly force, and how you have to store a gun at home — is largely a state question. A firearm you can legally own and carry in one state can lead to arrest the moment you cross a border.
The Federal Rules That Apply Everywhere
Any firearm sold by a licensed dealer runs through the same federal system. The Brady Handgun Violence Prevention Act requires licensed dealers to initiate a background check before completing a sale.1Bureau of Alcohol, Tobacco, Firearms and Explosives. Brady Permit Chart The buyer completes ATF Form 4473, and the dealer contacts the FBI’s National Instant Criminal Background Check System (NICS), which screens the buyer against criminal records, mental health adjudications, and restraining orders.2Federal Bureau of Investigation. Firearms Checks (NICS)
Federal minimum ages for purchases from licensed dealers are 18 for long guns and 21 for handguns.3Bureau of Alcohol, Tobacco, Firearms and Explosives. Minimum Age for Gun Sales and Transfers The 2022 Bipartisan Safer Communities Act allows NICS to extend the review period up to 10 business days for buyers under 21 whose check turns up a potentially disqualifying juvenile record. The same law expanded the domestic violence misdemeanor prohibition to include dating partners.4Congress.gov. Bipartisan Safer Communities Act
Federal prohibitions on possession apply nationwide. Anyone convicted of a felony, subject to certain domestic violence restraining orders, or adjudicated as mentally incompetent is banned from possessing firearms regardless of what any state permits.
How Purchase Rules Differ by State
Federal background checks only reach sales through licensed dealers. Private sales between individuals carry no federal check requirement, and this is where state approaches split. Roughly 19 states and the District of Columbia require universal background checks on all firearm transfers, including private sales. In the rest, a private seller has no legal obligation to verify the buyer’s eligibility.
Permits, Licenses, and Registration
Several states require a separate permit to purchase a firearm, involving a background investigation that often digs deeper than the federal check. A smaller group issues a Firearm Owner’s Identification card that functions as an ongoing license to possess firearms and ammunition, typically requiring renewal every few years. Some states also maintain firearm registries requiring owners to report the make, model, and serial number of each firearm acquired. Missing a registration deadline can create criminal exposure even for a law-abiding owner.
Waiting Periods
About a dozen states impose a mandatory waiting period between purchase and physical transfer, running from three days to as long as 14 days. Some apply the wait to all firearms; others limit it to handguns.
State Age Limits Above the Federal Floor
Federal law lets 18-year-olds buy rifles and shotguns from dealers, but a growing number of states have raised the minimum age for all firearms to 21. California, Florida, Hawaii, Illinois, and others have adopted the higher threshold, and these state limits typically apply to both dealer sales and private transfers.3Bureau of Alcohol, Tobacco, Firearms and Explosives. Minimum Age for Gun Sales and Transfers
Carrying in Public: Where the States Differ Most
How and whether you can carry a firearm in public is the biggest area of state-to-state variation. Carry regimes fall into a few broad categories.
Constitutional (Permitless) Carry
Twenty-nine states allow anyone who can legally possess a firearm to carry it concealed without a government-issued permit. Permitless does not mean rule-free: people in these states still face location-based restrictions, and many carriers still obtain a permit to make interstate travel easier under reciprocity agreements.
Shall-Issue States
In shall-issue states, the licensing authority must grant a concealed carry permit to any applicant who meets objective criteria — usually a clean criminal record, a minimum age (typically 21), and completion of a firearm safety course. Once an applicant meets the criteria, officials have no discretion to deny.
May-Issue States After Bruen
Before 2022, several states operated may-issue systems where local officials could deny permits to applicants who failed to show a special need for self-defense. In New York State Rifle & Pistol Association v. Bruen, the Supreme Court struck down that approach, holding that requiring applicants to show “proper cause” beyond ordinary self-defense violates the Constitution.5Supreme Court of the United States. New York State Rifle and Pistol Association Inc. v. Bruen The Court identified six states and the District of Columbia as having comparable proper-cause standards at the time. Those jurisdictions have been revising their frameworks, though some have responded by imposing extensive training requirements and expanding the list of places where carrying is prohibited.
Open Carry
Open carry is governed separately in most states. Some allow it without a permit, some require the same license used for concealed carry, and a few prohibit it entirely. Openly carrying where it is banned typically triggers immediate detention and can lead to felony charges and revocation of any carry privileges.
Duty to Inform Police
About a dozen states require you to tell a police officer immediately during any official interaction that you are carrying, even at a routine traffic stop. Others require disclosure only if the officer asks. Failing to volunteer the information in a mandatory-disclosure state can be a separate criminal charge from any underlying offense.
Traveling With a Firearm Across State Lines
Reciprocity agreements determine whether your home state’s carry permit is recognized in another state. Full reciprocity means all valid permits are honored. Partial reciprocity limits recognition to states with comparable training and background check standards. Some states recognize no out-of-state permits at all, so visitors must either leave firearms behind or obtain a non-resident permit in advance. These agreements change frequently, and a reciprocity map that was accurate six months ago may not be current now.
FOPA Safe Passage
Federal law offers a narrow protection for transporting firearms through states where you could not otherwise legally possess them. Under 18 U.S.C. § 926A, you can transport a firearm through any state as long as it is legal at both your origin and destination, the firearm is unloaded, and neither it nor the ammunition is readily accessible from the passenger compartment.6Office of the Law Revision Counsel. 18 USC 926A – Interstate Transportation of Firearms If your vehicle has no separate trunk or cargo area, both firearm and ammunition must sit in a locked container that is not the glove compartment or center console.
This protection covers only continuous, uninterrupted travel. An overnight hotel stay, a visit to a friend, or any extended stop in a restrictive state can strip the federal shield and expose you to local law. Some restrictive states have aggressively prosecuted travelers for brief stops.
Restrictions on Firearm Types and Accessories
Assault Weapon Bans
Ten states have enacted bans on what their statutes define as “assault weapons,” generally targeting semi-automatic rifles with features like pistol grips, adjustable stocks, or threaded barrels. Definitions and grandfathering provisions vary. In states with these bans, possessing a prohibited firearm can be a felony. Manufacturers have responded by producing “featureless” versions of popular rifle platforms.
National Firearms Act Items
Silencers (suppressors), short-barreled rifles, short-barreled shotguns, and machine guns are regulated federally under the National Firearms Act. Legal ownership requires a $200 tax, an extensive background check, and registration with the ATF. Full federal compliance does not preempt state law: many states ban some or all of these items outright, and possession in a state that prohibits them exposes you to both federal and state prosecution.7Office of the Law Revision Counsel. 26 USC 5871 – Penalties
Magazine Capacity Limits
Fourteen states and the District of Columbia restrict how many rounds a magazine can hold, though the D.C. ban is currently not being enforced following a 2026 court ruling. The most common cap is 10 rounds; some states set limits at 15, 17, or 20 depending on the firearm type. A few states use different caps for rifle and handgun magazines. Possession of an over-capacity magazine can be charged as a misdemeanor or felony depending on the state. This is one of the most common ways travelers get caught out: a standard-capacity magazine that is legal in most of the country becomes contraband when you drive into a restricted state.
Unserialized and Homemade Firearms
Homemade and 3D-printed firearms without serial numbers have drawn expanding regulation. A 2022 ATF rule requires federally licensed dealers to serialize any unserialized firearm that comes into their possession. Several states have enacted their own bans or serialization requirements for privately manufactured firearms. Some prohibit possession of any unserialized firearm; others require owners to apply for a state-issued serial number and engrave it on the weapon.
Where You Can’t Carry, Even With a Permit
Federal and state law carve out specific places where firearms are banned even for permit holders. The Gun-Free School Zones Act makes it a federal crime to knowingly possess a firearm within 1,000 feet of a school, with exceptions for people licensed by the state where the school is located and for firearms that are unloaded and in a locked container.8Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts Violations carry up to five years in federal prison.9Office of the Law Revision Counsel. 18 US Code 924 – Penalties
Most states also prohibit firearms in government buildings, courthouses, and polling places, and many extend the ban to bars, hospitals, and large public events. The Bruen decision acknowledged that governments can restrict firearms in “sensitive places” like legislative assemblies, polling places, and courthouses, and several states have since expanded their sensitive-location lists to include parks, public transit, and establishments serving alcohol.5Supreme Court of the United States. New York State Rifle and Pistol Association Inc. v. Bruen Whether every expanded designation will survive legal challenge is an open question.
Private property owners can generally ban firearms from their premises. In many states, posted signage carries the force of law: ignoring it can lead to a criminal trespass charge rather than a simple request to leave. Sign requirements vary; some states demand exact statutory language and specific dimensions, others honor any clear notice. Where no sign is posted, states differ on whether carry is allowed by default.
When You Can Legally Use a Firearm
Owning and carrying a firearm is one question. When you can legally use it is another, and self-defense laws vary significantly across states.
At least 31 states have enacted stand-your-ground laws, which remove any obligation to retreat before using force in self-defense as long as you are in a place where you have a right to be.10National Conference of State Legislatures. Self Defense and Stand Your Ground In these states, if you reasonably believe deadly force is necessary to prevent death or serious injury, you can respond without first trying to escape. The remaining states impose a duty to retreat, expecting you to avoid the confrontation if you can safely do so before resorting to force. A few states fall in between, eliminating the duty to retreat inside the home but keeping it in public.
The Castle Doctrine is the narrower version, applying to your home and, in some states, your vehicle or workplace. Nearly every state recognizes some form of it, allowing the use of force against someone who unlawfully enters or attempts to enter your dwelling. The practical difference matters: in a duty-to-retreat state, using deadly force in a parking lot can bring criminal liability even if you felt genuinely threatened; in a stand-your-ground state, the same action may be legally justified.
Red Flag Laws
Twenty-two states have enacted extreme risk protection order (ERPO) laws, often called red flag laws, which let designated individuals petition a court for a temporary order removing firearms from someone who poses a danger to themselves or others. The Bipartisan Safer Communities Act provided federal funding to help states establish or improve these programs.4Congress.gov. Bipartisan Safer Communities Act
Who can petition depends on the state. Law enforcement can file everywhere the law exists. Many states also allow family members, household members, medical professionals, and school officials to file. Courts typically issue a temporary ex parte order first, removing firearms before a full hearing, then hold a follow-up hearing where the subject can contest the order. Standards for the final order vary: some states require a preponderance of the evidence, others require clear and convincing evidence. Orders generally last between 6 and 12 months, after which the petitioner must seek renewal or the firearms are returned.
Safe Storage Requirements
Roughly half the states have some form of safe storage or child access prevention law, and the requirements vary widely. The strictest versions require secure storage any time a firearm is not in the owner’s immediate control, whether or not children are present. Others impose liability only after a child gains access to an unsecured firearm and causes harm. The definition of “child” ranges from under 14 to under 18 depending on the state.
Some states require dealers to include a locking device such as a cable lock or trigger lock with every firearm sold. Penalties for storage violations range from misdemeanors to felonies, often escalating if a minor was injured or killed. A few states extend storage obligations to households where a prohibited person, such as a convicted felon, resides. States without storage laws impose no legal obligation to secure firearms at all, so a gun owner moving between states can face a completely different legal standard.