How to I apply for permanent residency?

Usually permanent residents may apply for citizenship by naturalisation after a period of residence in the country concerned. In many nations an application for naturalisation can be denied on character grounds sometimes resulting in individuals that are not in danger of being deported but may not proceed to citizenship. In the United States, the residency requirements for citizenship may vary according to the basis for residency; for example, those who achieved legal permanent residence by marriage may apply for citizenship three years after residency was granted, while others must wait five years. Those who have served in the armed forces may qualify for an expedited process allowing citizenship after only one year.