While you're legally allowed to carry as much as you want, there are extreme risks to carrying large amounts of cash in the US. Not only could you be robbed by a criminal, but US police and airport security sometimes seize cash claiming that it must be related to criminal activity. Under American civil asset forfeiture laws, they do not need to convict you of any crime or even charge you with a crime to seize your cash. Once a law enforcement agency has your money, they make it extremely difficult and expensive to get it back even if you can prove it's not related to any criminal activity. People carrying cash to buy cars or other large items have had their money seized by police without any charges or warrants. Police departments are often allowed to use seized funds for their own budgets, so they're highly motivated to take cash whenever they find it. Never carry more cash than you can afford to lose.Civil forfeiture in the United StatesAsset Forfeiture AbuseThese states let police take and keep your stuff even if you haven't committed a crimeCollege student had his life savings seized by the cops even though he was never charged with a crime