The San Ysidro border crossing betweenSan Diego-Tijuana is the second busiest border crossing in the world.
A border checkpoint is a place, generally between two countries, where travellers or goods are inspected. Authorization often is required to enter a country through its borders. Access-controlled borders often have a limited number of checkpoints where they can be crossed without legal sanctions. Arrangements may be formed to allow or mandate less restrained crossings (e.g. Schengen Agreement). Land border checkpoints can be contrasted with the customs and immigration facilities at seaports, international airports, and other ports of entry.
Checkpoints generally serve two purposes:
- To prevent entrance of individuals who are either undesirable (e.g., criminals or others who pose threats) or are simply unauthorized to enter.
- To prevent entrance of goods that are illegal, subject to restriction or to collect tariffs.
Checkpoints are usually manned by a uniformed service (sometimes referred to as customs service or border Patrol Agents).
In some countries (e.g. China, Japan), there are border checkpoints when both entering and exiting the country; while in others (e.g. U.S., Canada), there are border checkpoints only when entering the country.