25 CFR § 580.6
How is time computed?
February 24, 2021
In computing any period of time prescribed for filing and serving a document, the first day of the period so computed shall not be included. The last day shall be included unless it falls on a Saturday, Sunday, or Federal legal holiday, in which case the period shall run until the end of the next business day. Except for appeals of temporary closure orders, when the period of time prescribed or allowed is less than 11 days, intermediate Saturdays, Sundays, and legal federal holidays shall be excluded from the computation.
[77 FR 58945, Sept. 25, 2012, as amended at 80 FR 31995, June 5, 2015]