Immigration is when people move from one country to another to live there permanently or for a long time. Someone who immigrates becomes an immigrant in their new country. For example, if a family moves from Mexico to the United States to build a new life, they are immigrating to the United States.

Throughout history, immigration has shaped nations and cultures. The United States, in particular, grew through waves of immigration: people came from Ireland during the potato famine of the 1840s, from China to work on the railroads in the 1860s, from Italy and Eastern Europe around 1900, and from many other places seeking opportunity or fleeing danger. These immigrants brought their languages, foods, traditions, and skills, which mixed together to create American culture as we know it.

People immigrate for many reasons. Some seek better jobs or education. Others join family members who moved earlier. Some flee war, persecution, or natural disasters. The reasons are as varied as the people themselves.

Immigration is different from emigration, which describes leaving your home country. The same journey involves both: you emigrate from one place and immigrate to another. It's also different from tourism or temporary visits. Immigrants intend to make their new country their home, learning its language, contributing to its economy, and often eventually becoming citizens.