What department is uscis in the United States?

Uscis belongs to the United States Department of Justice. Uscis is the United States Immigration Service.

The enforcement power of immigration law belongs to the Minister of Justice, but the Minister of Justice usually authorizes the Immigration Bureau, so the Immigration Bureau has become the core enforcement agency of immigration law, responsible for handling immigration and non-immigration applications, foreigners' entry and exit, border patrol, arrest and expulsion of illegal foreigners, refugee review, and punishment of illegal employment.

Ordinary foreigners have the most contact with four regional immigration service centers that directly accept immigration and non-immigration applications, as well as regional offices and sub-bureaus that handle daily immigration affairs. The latter is usually called "local office".