The following information is not legal advice. There is no substitute to reading and understanding the laws as they are actually written, and I encourage you to do just that.
Concealed carry is prohibited in posted public (meaning government) buildings. There is actually no law prohibiting open carry in most of these places.
You may not legally open carry onto the property of a school, day care facility, or property of the NV System of Higher Education (unless you have permission from the principal of the school or president of the college/university).
You may legally open carry onto any private property which is open to the public (including casinos), but you may be asked to disarm or leave by management or security. Failure to leave when asked to do so by the owner or manager of the property or some other authorized person could result in criminal trespass charges. Signs prohibiting carry on private property carry no weight of law in NV, but you probably shouldn't carry at posted businesses since you know the owner will not like it and will likely ask you to leave anyways.
