Immigration is the act of moving into a new country to live there. It has taken place throughout history and continues today. People may move for work, family, or safety.

Governments record immigration using systems such as visas, permits, and official documents. Some people stay for a short time, while others settle permanently. Large cities often receive many immigrants from different regions.

Immigration is measured using population data and national records. It is studied in geography and social sciences as part of migration systems.