Which entity processes the N-400 applications?

The United States Citizenship and Immigration Services (USCIS) is the entity responsible for processing N-400 applications, which is the form used by lawful permanent residents to apply for U.S. citizenship through naturalization. USCIS handles all aspects of immigration processing, including green card applications, asylum requests, and citizenship applications. This role involves not only the review of applications but also conducting interviews and overseeing the naturalization ceremonies.

The other entities mentioned do not typically handle applications for citizenship. The Department of State primarily deals with foreign affairs, including the issuance of visas and passports. The Civil Rights Office focuses on protecting civil rights, while the Department of Justice deals with federal legal matters, including immigration law enforcement, but does not process naturalization applications directly. Thus, USCIS is the correct choice for processing N-400 applications.