What is USCIS? It is the agency most immigrants deal with the most, and its name comes up in almost every part of a green card case. People search for it thousands of times a month, often because a form or notice mentions it and it is not clear how it fits with the other agencies.
As of October 31, 2026, this guide explains what USCIS does, how it came about, what it does not do, and how to deal with it.
- USCIS stands for U.S. Citizenship and Immigration Services.
- USCIS took over immigration service functions on March 1, 2003.
- It says it processes an average of 8 million applications, petitions and requests a year.
- The Department of State issues visas abroad; CBP handles entry at the border.
- ICE and CBP were created to oversee enforcement and border security.
- Your case number at USCIS is your receipt number, which is different from your A-Number.
What does USCIS stand for?
U.S. Citizenship and Immigration Services. It sits inside the Department of Homeland Security. USCIS says "on March 1, 2003, U.S. Citizenship and Immigration Services assumed responsibility for the immigration service functions of the federal government" (USCIS, Our History).
Before then, a single agency did both services and enforcement. USCIS says "INS oversaw the immigration process, enforcement, and border patrol activities for 70 years until Congress passed the Homeland Security Act of 2002." It says the new agency "was founded to enhance the security and efficiency of national immigration services by focusing exclusively on the administration of benefit applications." The same law "created Immigration and Customs Enforcement and Customs and Border Protection to oversee immigration enforcement and border security."
What does USCIS actually do?
It decides requests for immigration benefits. You will see these common forms:
| Form | What it is for |
|---|---|
| I-130 | Petition for a relative |
| I-140 | Petition for an immigrant worker |
| I-129 | Petition for a nonimmigrant worker, such as H-1B or O-1 |
| I-485 | Green card application in the United States |
| I-765 | Work permit |
| I-131 | Travel documents, such as advance parole |
| I-90 | Replacing or renewing a green card |
| N-400 | Naturalization |
The scale is large. USCIS says it "processes an average of 8 million applications, petitions, and requests annually" (USCIS, Understanding Our H-1B Employer Data Hub).
It is also where the rules become practical. Officers apply the USCIS Policy Manual, and the agency publishes processing times and data. Our guide to USCIS processing times explains how to read them.
What does USCIS not do?
Three common mix-ups.
It does not issue visas abroad. That is the Department of State. USCIS says if you are outside the country, "you may apply at a U.S. Department of State consulate abroad for an immigrant visa" (USCIS, Consular Processing). Our guide to NVC and consular processing explains those steps.
It does not inspect you at the airport. U.S. Customs and Border Protection does that. A USCIS approval does not by itself guarantee admission. For example, USCIS says of a green card holder arriving at a port of entry that "a U.S. Customs and Border Protection Officer will review your permanent resident card and any other identity documents you present" (USCIS, International Travel as a Permanent Resident).
It does not certify PERM or LCAs. The Department of Labor does. Our guide to PERM step by step covers that stage. USCIS sees the result when an employer files the I-140 or H-1B petition.
Here is the overall picture:
| Agency | Role you will notice |
|---|---|
| USCIS (DHS) | Decides benefit requests |
| CBP (DHS) | Admits people at ports of entry and issues I-94 records |
| ICE (DHS) | Interior enforcement; oversees the student SEVIS program |
| Department of State | Visas at consulates; Visa Bulletin |
| Department of Labor | PERM, LCAs and prevailing wages |
| Immigration courts | Removal cases, under the Department of Justice |
What does it mean when USCIS adjudicates a case?
It means an officer decides it. The USCIS glossary defines adjudication as "USCIS' review of a petition or application to determine if an alien is eligible for that immigration benefit" (USCIS, Glossary). That review can end in an approval or a denial, and it may include a request for more evidence or an interview along the way. Our guide to responding to an RFE covers one common step. Approval by USCIS is also not the end of the road in many cases, since a visa number or an entry at the border may still be needed.
How is USCIS funded?
Mostly through filing fees, which is why it can keep working when other parts of government cannot. In an archived 2018 notice, USCIS said a lapse in appropriated funding "does not affect USCIS's fee-funded activities" (USCIS, Lapse in Federal Funding, archived). Some of its programs depended on separate appropriations or reauthorization, so a funding lapse can still touch specific services. It also explains why fee schedules change, and why it pays to check the current fee before filing.
How do you interact with USCIS?
Mostly by mail, online and through appointments. You can file many forms online. USCIS says that "once you have an account, you will be able to file forms and pay fees from your computer, phone, or tablet" (USCIS, How to Create a USCIS Online Account). Some forms still go by mail, and filing locations can change. In October 2026, for example, USCIS "changed the filing location for Form I-539" (USCIS, Form I-539). So check the form page each time.
Expect two kinds of in-person contact. A biometrics appointment takes fingerprints, photos and a signature, and an interview may follow. Your appointment notice tells you what to bring.
How do you check on your case?
With your receipt number. USCIS says "to check your case status using our online tool, you have to have your case receipt number," which is "a unique 13-character identifier" (USCIS, Checking Your Case Status Online). Our guide to USCIS case status walks through it.
If you need to reach a person, the same page gives "the USCIS Contact Center at 1-800-375-5283." USCIS also offers "how to submit an inquiry about your case (e-Request)." Before you contact them, compare your case with the posted processing time.
What numbers does USCIS use?
Three that people often confuse.
- Receipt number. Identifies one filing; it has three letters and 10 numbers.
- A-Number. Identifies you across your immigration records.
- USCIS Online Account Number. "A unique identification number issued by the USCIS online filing system account" (USCIS, Glossary). It is not the same as an A-Number.
How do you avoid scams?
Use official channels. USCIS points people to its Avoid Scams page and warns that "if you need help or legal advice on immigration matters, make sure the person helping you is authorized to give legal advice" (USCIS, Unlawful Presence and Inadmissibility). Check that any website you pay is a real .gov page or a qualified representative. USCIS is a federal agency, and legitimate government websites use .gov.
What this means for you
- Learn which agency handles each stage of your case.
- Use your receipt number for USCIS status, and keep it separate from your A-Number.
- Read the form page before each filing, because addresses and editions change.
- Update your address with USCIS within 10 days of moving.
- Be careful with anyone offering a shortcut.
Where to start
If you are working out which immigration path fits you, our free evaluation at /evaluate/ checks whether EB-1A or the NIW fits your profile, and Frank, our AI assistant at /frank, helps you build the evidence. Petitions are reviewed and filed by our partner law firm, Lai & Turner.
Sources
All checked October 31, 2026.
- USCIS, Our History. 2003 start; INS; ICE and CBP.
- USCIS, Understanding Our H-1B Employer Data Hub. Annual volume.
- USCIS, Consular Processing. Department of State role.
- USCIS, International Travel as a Permanent Resident. CBP at the port of entry.
- USCIS, How to Create a USCIS Online Account. Online filing.
- USCIS, Form I-539. Filing location alert.
- USCIS, Checking Your Case Status Online. Receipt number; contact options.
- USCIS, Glossary. USCIS Online Account Number.
- USCIS, Unlawful Presence and Inadmissibility. Authorized legal help.
- USCIS, Lapse in Federal Funding (2018, archived). Fee funding.
Frequently asked questions
What does USCIS stand for?
U.S. Citizenship and Immigration Services. It is part of the Department of Homeland Security. USCIS says that on March 1, 2003, it assumed responsibility for the immigration service functions of the federal government. Before that, the Immigration and Naturalization Service, or INS, handled immigration services and enforcement together for about 70 years.
What does USCIS do?
It decides immigration benefit requests. These include immigrant petitions, green card applications, work permits, travel documents, extensions and changes of nonimmigrant status, and naturalization. USCIS also runs biometrics appointments and interviews and publishes its policy manual, forms and processing times. It does not run the border, and it does not issue visas at consulates.
Is USCIS the same as immigration or ICE?
No. People use the word immigration to cover several agencies. USCIS handles benefit applications. Immigration and Customs Enforcement and Customs and Border Protection were created to oversee immigration enforcement and border security. The Department of State issues visas abroad, and the Department of Labor handles labor certifications. Your case may touch more than one of them.
How do I check my case with USCIS?
Use the online case status tool with your 13-character receipt number, or create a free online account to see case updates. USCIS also offers an e-Request tool for some inquiries and a Contact Center at 1-800-375-5283. It says you should check processing times for your form before submitting an inquiry about a delay.
Do I need a lawyer to deal with USCIS?
USCIS forms can be filed without one in many cases, and the agency publishes instructions for each form. If you get help, USCIS warns people to make sure the person helping is authorized to give legal advice, and it maintains an Avoid Scams page on authorized legal services. Complex cases, denials and any court matter call for an attorney.
Green Card Guide AI is not a law firm and this article is not legal advice. It describes evidence-building strategy in general terms; your attorney determines what belongs in your petition and how it's argued.
