Naturalisation is never an overnight process. It requires complicated paperwork, long wait times, and intensive interview. To be honest, the overall approval process can last several months or years. While there is no guaranteed time frame for naturalisation, there is a range that seems to apply in most cases.
While the US Citizenship and Immigration Services (USCIS) does not restrict the processing of citizenship applications to a specific time frame, it is common for many applicants to be interviewed and approved for citizenship within 12 to 15 months from their original application date.
Changes in fees and new citizenship requirements can slow wait times as the USCIS experiences a flood of new applicants seeking to apply before such changes go into effect.
Immigrants seeking citizenship without a U.S. spouse traditionally have to wait longer than those who do have a U.S. spouse.
As of October 2001, the USCIS reported that the complete citizenship application process ranges, on average, between 6 and 9 months.
Errors or incomplete paperwork can delay the citizenship application process by months. Any changes that are needed will be addressed via mail and must be returned to the USCIS within a specified period of time.