This what is mentioned on CIS website....for 1485 application
IF you live in Alaska, Arizona, California, Colorado, Guam, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, North Dakota, Ohio, Oregon, South Dakota, Utah, Washington, Wisconsin or Wyoming, send your application to the Nebraska Service Center.
USCIS
Nebraska Service Center
P.O. Box 87485
Lincoln, NE 68501-7485
If you live in any other state, U.S. territory, or Washington, D.C., send your application to the Texas Service Center.
USCIS
Texas Service Center
P.O. Box 851804
Mesquite, TX 75185-1804