Illegal immigration refers to the illegal immigration of people across a country's borders in a way that violates the immigration laws of the country, with intentions to remain in the country. Illegal immigration can also occur when people remain living in a country when they no longer have the legal right to do so.
Illegal immigration, as well as immigration in general, is overwhelmingly financially upward, from a poorer to a richer country. Living in another country illegally includes a variety of restrictions, as well as the risk of being detained and deported or of facing other sanctions.
Asylum seekers who were denied asylum may face impediment to expulsion, for example if the home country refuses to receive the person or if new asylum reasons occur after the decision. In some countries or cases, these people are considered as illegal immigrants, and in others, they may get a temporary residence permit, for example with reference to the principle of non-refoulement in the international Refugee Convention. The European Court of Human Rights, referring to the European Convention on Human Rights, has shown in a number of indicative judgments that there are enforcement barriers to expulsion to certain countries, for example due to the risk of torture.