Same place as for a 1040 form.
https://www.irs.gov/filing/where-to-file-addresses-for-taxpayers-and-tax-professionals-filing-form-1...
Arkansas,
Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Montana,
Nebraska, North Dakota, Ohio, Oklahoma, South Dakota, Wisconsin
Department of the Treasury
Internal Revenue Service
Fresno, CA 93888-0002