25 CFR §2.203

1. (a)You have 30 days after you receive a copy of the decision you are appealing to file a Notice of Appeal, except as provided in § 2.104(b).
2. (b)We will presume that you have received notice of the decision 10 days after the date that the decision was mailed to you, if the decision-maker mailed the document to the last address the decision-maker has on file for you.
3. (c)If the reviewing official receives proof that the document was delivered before the expiration of the 10-day period, you are presumed to have received notice on the date of delivery, and you have 30 days from that date to file an appeal.