If your US citizenship application is denied by the USCIS, you will not become a US citizen. However, you may file a US citizenship application again after five years after correcting the reasons for denial. However, if you are found to be inadmissible into the country, your Green Card will be revoked and you will be removed from the country. Though you carefully prepare your US citizenship application, your application is likely to be denied for various reasons.
USCIS will deny your application if you are ineligible for US citizenship and if you do not meet the prerequisites for citizenship. You may be denied US citizenship, if you are found to be a criminal or if you do not meet the residency requirements. Similarly, if you do not get through the US citizenship tests, your application will be denied. However, if you fail to get through the English or the Civics test, you will be given another chance to take the test. If you get through, you will be granted US citizenship. If not, you will have to start the naturalization application process again and you must fill out Form N-400 and pay the filing fee again. However, you may remain in the country as a lawful permanent resident, even if your US citizenship application is denied.
After you file your application, if the USCIS officers find that you do not meet they residency requirements, your application will be denied and in such cases, you may file your US citizenship application again after you meet the requirements. If the USCIS officers find that you lack good moral character, your application will be denied. Similarly, US citizenship applications are also denied based on criminal convictions. However, you can appeal, if you are denied US citizenship and you need to file the appeal within 30 days from the date of receiving the decision.
To request a hearing you will have to file Form N-336, Request for a Hearing on a Decision in Naturalization Proceedings and you will have to explain why you feel that the denial of your application is incorrect. After you file this form, you will be required to appear for an interview and this interview will not be conducted by the same USCIS officer who denied your citizenship application. You will have to take with you the required supporting documents to prove that you are eligible for US citizenship and that the denial is incorrect. If this appeal process is not successful, you may appeal the decision to the federal district court and request the court to review your application.