A castle doctrine is a self-defense law that states that a person’s home (sometimes also a place of work or vehicle) is a place that grants one protection and immunity from prosecution in certain circumstances to use force or deadly force to defend oneself against an intruder. There is no duty to retreat from the situation in one’s home (or workplace or vehicle if applicable) before using force, but there may be a duty to retreat in a public place.

The United States has two different self-defense laws. The “Stand Your Ground” Law states that there is no duty to retreat from the situation before using deadly force and is not limited to one’s home, place of work, or vehicle. The “Duty to Retreat” Law states that one cannot harm another in self-defense when it is possible to retreat from a threatening situation to a place of safety. In all duty-to-retreat states, the duty to retreat does not apply when the defender is in their own home. States may have both a Castle Doctrine and a Stand Your Ground variation, such as Iowa.