According to the NRA, the Law Enforcement Officer Safety Act (LEOSA), allows retired officers to carry concealed weapons after retirement in any U.S. State or territory. However, there are a few caveats to this rule, and officers should apply for special LEOSA photographic identification first, and take the pre-requisite firearms test.
Although the concealed carry law applies regardless of which state the ex-officer is in — there are places where an ex-cop can be told to put the gun down. Any person can refuse a retired officer the right to carry a gun on their private property for example, and LEOSA rules do not apply to common gun-free zones such as schools and national parks. Carriers must pay attention to such restrictions, which are often in place in federal government buildings. Flying with a gun is also a big no-no — and applies as much to retired officers as it does to everyone else.
Cops who have gone over to the dark side — also waive their rights under LEOSA. Anybody convicted of a criminal offense punishable by a year or more in jail, cannot carry, nor can anybody subject to a court order for stalking or harassing and threatening an intimate partner or child. Other common prohibitions that limit gun ownership rights — such as mental illness, and being high on illicit substances, naturally, still apply to ex-police officers.