<human>:  What are the laws regarding gun ownership in the US?
<bot>: The laws regarding gun ownership in the United States vary from state to state. Generally, individuals must be at least 18 to purchase a firearm from a licensed dealer, and 21 to purchase a handgun. A valid state-issued ID and background check are typically required in order to purchase any type of firearm. In addition, some states have stricter laws that may require additional paperwork and/or licensing in order to purchase, own, or carry firearms. Additionally, federal laws prohibit individuals convicted of a felony or deemed mentally unfit to purchase, own, or carry firearms.