17 U.S.C. § 703: Effective date of actions in Copyright Office

In any case in which time limits are prescribed under this title for the performance of an action in the Copyright Office, and in which the last day of the prescribed period falls on a Saturday, Sunday, holiday, or other nonbusiness day within the District of Columbia or the Federal Government, the action may be taken on the next succeeding business day, and is effective as of the date when the period expired.