It is LEGAL to carry a firearm into private businesses with “No Weapon” and “No Firearm” signs.
Utah law states a “secure area” may not include any area normally accessible to the public.
This means that businesses who post these signs Do Not have the force of law, but businesses may have policies that can restrict a person from carrying a firearm. When going in businesses with these signs and carrying a firearm, either open or concealed, you are ignoring the property owner’s policies. If you are asked to leave by the owner or any employee of the business, you must leave. If you refuse to leave you could be charged with criminal offenses such as criminal trespass and/or disorderly conduct. Always be aware of the possibility that the responding law enforcement who may have been called without your knowledge could arrest you even if you are within the law.

Businesses or private property owners that do not post “no gun” signs or who knowingly allow a person to carry a concealed firearm onto the owner’s property are not civilly or criminally liable for any damage or harm resulting from the discharge of the firearm on the owner’s property as explained in 53-5a-103.

The only statutory restrictions are prohibited areas listed in 53-5-710. For more information about these areas click here.

Laws

76-6-206.  Criminal trespass.
(1) (a) As used in this section:
(i) "Enter" means intrusion of the entire body or the entire unmanned aircraft.
(ii) "Graffiti" means the same as that term is defined in Section 76-6-101.
(iii) "Remain unlawfully," as that term relates to an unmanned aircraft, means remaining on or over private property when:
(A) the private property or any portion of the private property is not open to the public; and
(B) the person operating the unmanned aircraft is not otherwise authorized to fly the unmanned aircraft over the private property or any portion of the private property.
(b) Terms defined in Sections 76-1-101.5 and 76-6-201 apply to this section.
(2) A person is guilty of criminal trespass if, under circumstances not amounting to burglary as defined in Section 76-6-202, 76-6-203, or 76-6-204 or a violation of Section 76-10-2402 regarding commercial obstruction:
(a) the actor enters or remains unlawfully on or causes an unmanned aircraft to enter and remain unlawfully over property and:
(i) intends to cause annoyance or injury to any person or damage to any property, including the use of graffiti;
(ii) intends to commit any crime, other than theft or a felony; or
(iii) is reckless as to whether the actor's or unmanned aircraft's presence will cause fear for the safety of another;
(b) knowing the actor's or unmanned aircraft's entry or presence is unlawful, the actor enters or remains on or causes an unmanned aircraft to enter or remain unlawfully over property to which notice against entering is given by:
(i) personal communication to the actor by the owner or someone with apparent authority to act for the owner;
(ii) fencing or other enclosure obviously designed to exclude intruders; or
(iii) posting of signs reasonably likely to come to the attention of intruders; or
(c) the actor enters a condominium unit in violation of Subsection 57-8-7(8).
(3) (a) Except as provided in Subsection (3)(b), a violation of Subsection (2)(a) or (b) is a class B misdemeanor.
(b) If a violation of Subsection (2)(a) or (b) is committed in a dwelling, the violation is a class A misdemeanor.
(c) A violation of Subsection (2)(c) is an infraction.
(4) It is a defense to prosecution under this section that:
(a) the property was at the time open to the public; and
(b) the defendant complied with all lawful conditions imposed on access to or remaining on the property.
(5) In addition to an order for restitution under Section 77-38b-205, an actor who commits a violation of Subsection (2) may also be liable for:
(a) statutory damages in the amount of three times the value of damages resulting from the violation of Subsection (2) or $500, whichever is greater; and
(b) reasonable attorney fees not to exceed $250, and court costs.
(6) Civil damages under Subsection (5) may be collected in a separate action by the property owner or the owner's assignee.

76-10-2402. Commercial obstruction -- Penalties.
(1) (a) A person is guilty of a misdemeanor if the person enters or remains unlawfully on the premises of or in a building of any business with the intent to interfere with the employees, customers, personnel, or operations of a business through any conduct that does not constitute an offense listed under Subsection (2).
(b) A violation of Subsection (1)(a) is a class A misdemeanor.
(2) A person is guilty of felony commercial obstruction if the person enters or remains unlawfully on the premises or in a building of any business with the intent to interfere with the employees, customers, personnel, or operations of a business and also with the intent to:
(a) obtain unauthorized control over any merchandise, property, records, data, or proprietary information of the business;
(b) alter, eradicate, or remove any merchandise, records, data, or proprietary information of the business;
(c) damage, deface, or destroy any property on the premises of the business;
(d) commit an assault on any person; or
(e) commit any other felony.
(3) A person who violates any provision in Subsection (2) is guilty of a second degree felony.
(4) This section does not apply to action protected by the National Labor Relations Act, 29 U.S.C. Section 151 et seq., or the Federal Railway Labor Act, 45 U.S.C. Section 151 et seq.
(5) This section does not apply to a person's exercise of the rights under the First Amendment to the Constitution of the United States or under Article I, Sec. 15 of the Utah Constitution.

76-9-102.  Disorderly conduct.
(1) As used in this section:
(a) "Official meeting" means:
(i) a meeting, as defined in Section 52-4-103;
(ii) a meeting of the Legislature, the Utah Senate, the Utah House of Representatives, a legislative caucus, or any committee, task force, working group, or other organization in the state legislative branch; or
(iii) a meeting of an entity created by the Utah Constitution, Utah Code, Utah administrative rule, legislative rule, or a written rule or policy of the Legislative Management Committee.
(b) "Public place" means a place to which the public or a substantial group of the public has access, including:
(i) streets or highways; and
(ii) the common areas of schools, hospitals, apartment houses, office buildings, public buildings, public facilities, transport facilities, and shops.
(2) An individual is guilty of disorderly conduct if:
(a) the individual refuses to comply with the lawful order of a law enforcement officer to move from a public place or an official meeting, or knowingly creates a hazardous or physically offensive condition, by any act that serves no legitimate purpose; or
(b) intending to cause public inconvenience, annoyance, or alarm, or recklessly creating a risk of public inconvenience, annoyance, or alarm, the person:
(i) engages in fighting or in violent, tumultuous, or threatening behavior;
(ii) makes unreasonable noises in a public place or an official meeting;
(iii) makes unreasonable noises in a private place which can be heard in a public place or an official meeting; or
(iv) obstructs vehicular or pedestrian traffic in a public place or an official meeting.
(3) The mere carrying or possession of a holstered or encased firearm, whether visible or concealed, without additional behavior or circumstances that would cause a reasonable person to believe the holstered or encased firearm was carried or possessed with criminal intent, does not constitute a violation of this section. Nothing in this Subsection (3) may limit or prohibit a law enforcement officer from approaching or engaging any person in a voluntary conversation.
(4) An individual who violates this section is guilty of:
(a) except as provided in Subsection (4)(b), (c), or (d), an infraction;
(b) except as provided in Subsection (4)(c) or (d), a class C misdemeanor, if the violation occurs after the individual has been asked to cease conduct prohibited under this section;
(c) except as provided in Subsection (4)(d), a class B misdemeanor, if:
(i) the violation occurs after the individual has been asked to cease conduct prohibited under this section; and
(ii) within five years before the day on which the individual violates this section, the individual was previously convicted of a violation of this section; or
(d) a class A misdemeanor, if:
(i) the violation occurs after the individual has been asked to cease conduct prohibited under this section; and
(ii) within five years before the day on which the individual violates this section, the individual was previously convicted of two or more violations of this section.

76-8-311.3. Items prohibited in correctional and mental health facilities -- Penalties.
(1) As used in this section:
(c) "Correctional facility" means:
(i) any facility operated by or contracting with the Department of Corrections to house offenders in either a secure or nonsecure setting;
(ii) any facility operated by a municipality or a county to house or detain criminal offenders;
(iii) any juvenile detention facility; and
(iv) any building or grounds appurtenant to the facility or lands granted to the state, municipality, or county for use as a correctional facility.
This means all jails, prisons, or other facilities where criminals who have been arrested are kept.

(f) "Mental health facility" means the same as that term is defined in Section 62A-15-602.
Same as described under 76-8-311.1 Secure areas -- Items prohibited -- Penalty. explained above.

(i) "Secure area" means the same as that term is defined in Section 76-8-311.1.
Same as described under 76-8-311.1 Secure areas -- Items prohibited -- Penalty. explained above.

(2) Notwithstanding Section 76-10-500, a correctional or mental health facility may provide by rule that no firearm, ammunition, dangerous weapon, implement of escape, explosive, controlled substance, spirituous or fermented liquor, medicine, or poison in any quantity may be:
(a) transported to or upon a correctional or mental health facility;
(b) sold or given away at any correctional or mental health facility;
(c) given to or used by any offender at a correctional or mental health facility; or
(d) knowingly or intentionally possessed at a correctional or mental health facility.
(3) It is a defense to any prosecution under this section if the accused in committing the act made criminal by this section with respect to:
(a) a correctional facility operated by the Department of Corrections, acted in conformity with departmental rule or policy;
(b) a correctional facility operated by a municipality, acted in conformity with the policy of the municipality;
(c) a correctional facility operated by a county, acted in conformity with the policy of the county; or
(d) a mental health facility, acted in conformity with the policy of the mental health facility.
Goes into detail explaining how firearms, ammunition, and other dangerous weapons are prohibited and cannot be brought onto the property for any reason.

(4)(a) An individual who transports to or upon a correctional facility, or into a secure area of a mental health facility, any firearm, ammunition, dangerous weapon, or implement of escape with intent to provide or sell it to any offender, is guilty of a second degree felony.
Yep, its a felony.
(b) An individual who provides or sells to any offender at a correctional facility, or any detainee at a secure area of a mental health facility, any firearm, ammunition, dangerous weapon, or implement of escape is guilty of a second degree felony.
Yep, this is a felony too.
(c) An offender who possesses at a correctional facility, or a detainee who possesses at a secure area of a mental health facility, any firearm, ammunition, dangerous weapon, or implement of escape is guilty of a second degree felony.
Yep, its still a felony.
(d) An individual who, without the permission of the authority operating the correctional facility or the secure area of a mental health facility, knowingly possesses at a correctional facility or a secure area of a mental health facility any firearm, ammunition, dangerous weapon, or implement of escape is guilty of a third degree felony.
Yep, and finally, this is also a felony.

53-5-704. Bureau duties -- Permit to carry concealed firearm -- Certification for concealed firearms instructor -- Requirements for issuance -- Violation -- Denial, suspension, or revocation -- Appeal procedure.
(3)(b) The bureau may not deny, suspend, or revoke a concealed firearm permit solely for a single conviction of an infraction violation of Title 76, Chapter 10,Part 5, Weapons.

53-5a-103. Discharge of firearm on private property -- Liability.
(1) As used in this section:
(a) "Firearm possessor" means an individual who may lawfully possess a firearm.
(b) "Property occupant" means:
(i) a private property owner; or
(ii) a person who has the right to occupy a private property under an agreement.
(2) Except as provided under Subsection (3), a property occupant, who knowingly allows a firearm possessor to lawfully bring a firearm onto the occupant's property, is not civilly or criminally liable for any damage or harm resulting from the discharge of the firearm by the firearm possessor while on the occupant's property.
(3) Subsection (2) does not apply if the property occupant solicits, requests, commands, encourages, or intentionally aids the firearm possessor in discharging the firearm while on the occupant's property for a purpose other than the lawful defense of an individual on the property.
(4) This section does not alter the responsibilities a tenant owes to a landlord under the terms of the lease agreement entered into between the tenant and landlord.