Border control is a term that describes how a country polices its borders. In most countries a Customs service of some sort controls the flow of people, animals and goods across a border. Reasons for having border controls include:

• Limiting immigration.
• Controlling the movement of citizens.
• Collecting excise taxes.
• Preventing smuggling of drugs, weapons, endangered species and other illegal or hazardous materials.
• Controlling the spread of human or animal diseases. (See also: quarantine)

The degree of strictness of border controls depends on the country and the border concerned. In some countries, control may be targeted at the traveller's national origin or other countries that have been visited. Others may need to be certain the traveller has paid the appropriate fees for their visas and has future travel planned out of the country. Yet others may concentrate on the contents of the travellers baggage, and imported goods to ensure nothing is being carried that might bring a biosecurity risk into the country.