What is the general mailing address for patent applications and patent-related papers?

The general mailing address for patent applications and patent-related papers is:

Commissioner for Patents
P.O. Box 1450
Alexandria, Virginia 22313-1450

This address should be used for correspondence including patent applications, replies to notices of informality, requests for extension of time, notices of appeal, briefs, requests for oral hearings, applications for patent term extensions, reexamination requests, statutory disclaimers, certificates of correction, petitions, and other patent-related correspondence processed by organizations reporting to the Commissioner for Patents.

As stated in MPEP 501: “Correspondence in patent-related matters under the direction of the Commissioner for Patents should be addressed to: Commissioner for Patents, P.O. Box 1450, Alexandria, Virginia 22313-1450”