The basic requirement is that the individual should be a green card holder who is at least 18 years old. The requirements related to residency must be satisfied while applying for citizenship. In normal circumstances, an immigrant should be a permanent resident for five years to be eligible for citizenship. If married to a US citizen, then it is three years of permanent residency. It is that the applicant should be married to a U.S citizen and should be living with that U.S citizen for the past 3 three years of their permanent residency for the criteria to be applicable. The applicant should have lived for at least three months in the same state or USCIS district where the application is going to be filed. Apart from this the other requirements include the good moral character, adequate knowledge of written and spoken English and US history as well as an attachment to the US constitution.