The U.S. Immigration Bureau detained illegal immigrants for up to 6 months in jail to prepare for deportation. To the Immigration Bureau, of course, the sooner they deport the better, the provincial detainee will occupy a prison position. (Originally, prisons are overcrowded), which consumes custody costs. Every time a prisoner is detained in the United States, it costs about US$30,000 to US$40,000 per year, providing food and drink, hiring police to watch the prisoners, and building a tight prison, but it needs to be completed before deportation. Two things: go through the necessary identity procedures and confirm that the prisoner is a citizen of a certain country and that the country is willing to accept him. Some smugglers who sneak into the United States by climbing over the wall do not have a passport (for example, tearing off the passport), and the country of nationality recognized by the prisoner does not have this. If a person is identified, the person becomes a "stateless person", which requires a long period of detention to finally confirm his or her nationality. However, most people whose identities can be confirmed will be deported from the United States in about a week; another thing that needs to be confirmed is whether the person is There are lawsuits that have not yet been resolved. Many detainees or their family members will submit complaints, such as submitting a "request for a stay of deportation" on the grounds of various family difficulties or illness, etc., or the person may have criminal proceedings in the United States. All Deportation is only possible after the lawsuit is settled, which requires a longer period of detention, or even several years, before deportation.