Most urban areas in California are no-gun (or "gun free" zones) because the only people who can legally carry are those with Licenses to Carry. Thus, most of this information will be applicable to licensees.
Open carry, loaded or unloaded, is only permitted in unincorporated areas (not part of an official city or town), where it is otherwise permitted to shoot guns (discharge a firearm). Thus, open carry is only permitted in rural/back country type areas at times of the seasons when target shooting is allowed.

School Zones

You may not:
  • Bring a firearm on to school/college/university property, even with a license to carry; or
  • Bring ammunition onto school property unless it is in a locked container;
  • Openly carry a handgun within 1,000 feet of a K-12 school.
 
Handguns must be transported unloaded, in a locked case, through a school zone.
Licensees are no longer allowed to carry on K-12 school property, even with permission.
Federal law does not grant an exemption to CCW licenses recognized through reciprocity.
Areas where you may legally openly carry may be within a school zone.

Public Buildings

Licensees are bound by the terms of their licenses, which may include a condition banning carry in public buildings.

  • You cannot carry firearms in any state or local public building without a license to carry.
  • You cannot carry at a public meeting, whether at a public building or not.
  • Licensees may carry in public buildings, except a courtroom when they are a party before the court.
  • Gun show attendees are exempt from this restriction if selling/trading/exhibiting.
  • You cannot carry into the State Capitol or on the capitol grounds.
  • You cannot have a firearm at, or within 100 feet, of a polling place.
  • Schools, universities, parks, and playgrounds have different restrictions (see school zone section).

Federal facilities

  • You may not carry a firearm in a federal building or courthouse.
  • You may not carry a firearm into a post office.
  • You may not carry at a VA hospital, facility, veteran's home, or a cemetery.

Other

Note: these appear to be restrictions on the facility, not licensed concealed carriers. Use caution. At a minimum, refusal to disarm or leave could be a trespassing offense.
All codes are from the Penal Code unless otherwise indicated. Codes may have omissions and abridgments made for the sake of brevity. All emphasis has been added, except certain terms leading definition statutes or regulations may be italicized in the original. All statutes and regulations should be reviewed in the original for their completeness. This does not constitute, nor should be implied as, legal advice. Always seek an attorney's advice and consult state and local laws yourself. User assumes all liability for use of the information provided here. Copyright 2021.