No, it is not illegal to carry any amount of cash in the U.S., UK, or EU in 2026, but it can be highly risky due to Civil Asset Forfeiture laws. While there is no legal limit on how much physical currency you can possess, authorities have the power to seize it if they have a "reasonable suspicion" that the money is tied to criminal activity, such as money laundering or drug trafficking. If you are traveling internationally, you must declare any amount exceeding $10,000 (or €10,000/£10,000) to customs; failing to do so is a crime and can result in the full amount being confiscated. In 2026, carrying large sums is increasingly discouraged because many businesses have moved to "cashless" models, making high-value physical currency less practical and more likely to trigger unwanted scrutiny from law enforcement or security personnel.