The address for a federal tax return will vary depending on the state it is sent from, but it will always be addressed to the "Department of the Treasury, Internal Revenue Service." In calendar year 2015 it will be sent to either Kansas City, Missouri; Fresno, California; or Austin, Texas.
In the Northeast and South, any tax return that doesn't include a payment should be sent to "Kansas City, Missouri 64999-0002." For states in the western United States, use "Fresno, California 93888-0002." The only special cases are the states of Florida, Louisiana, Texas and Mississippi. These states use the mailing address "Austin, Texas 73301-0002." For those who are non-residents, the return should be addressed to "Austin, Texas 73301-0215."