Illegal immigration

Illegal immigration is the migration of people into a country in violation of the immigration laws of that country or the continued residence without the legal right to live in that country. An illegal immigrant is an immigrant who lives in a country without permission or in a way that is not allowed, or illegal. Millions of people around the world live in another country against the laws of that country. 
Many of these people migrate to a country in secret. Many others come to the country legally as a visitor, then stay in the country when they should legally going home. Some work illegally and live in bad conditions. They usually move for similar reasons as other immigrants, but they do not legally have the right to be there.
In the United States.
Thousands of immigrants illegally enter the United States each year, many crossing the Mexican border. In general, they are opposed by the Republican Party, which generally wishes to deport them, while in general Democrats want to help give illegal immigrants legal status. In 2016, Donald Trump ran on a bid to build a wall on the Mexican-American border to prevent further illegal immigration. He became president in 2017, but the building of the border barrier was halted in 2021 when Joe Biden replaced Trump as president.