Beginning this year, estate and gift tax returns have new filing locations, according to the instructions for Form 706 and Form 709.

As of June 30, 2019, estate tax returns (Forms 706) filed using the United States Postal Service are to be sent to:

Department of the Treasury
Internal Revenue Service Center
Kansas City, MO 64999

However, Forms 706 filed using an approved private delivery service are to be sent to:

Internal Revenue Service
333 W. Pershing Road
Kansas City, MO 64108

The same filing addresses also already apply to gift tax returns (Forms 709), effective as of January 1, 2019.