(These links are heinous.)
Estimates of fatalities range from 80% to 98% of native inhabitants during the European invasion. Regarding "what makes a genocide," if one group of people totally obliterates another, that is definitely genocide. By this marker, America has the highest number of completed genocides known. Hitler did a lot of damage but didn't even succeed in wiping out one group, just came close. Despite the wars and massacres, germ warfare ultimately did more damage. Population of the Americas has been estimated between 8.4 million and 112.5 million. There were once over 600 tribes. Here is a partial list of tribes. There used to be over 300 languages spoken in North America. Here is a list of 109 languages of North America that have gone extinct (or more properly, dormant). About 154 tribal languages remain, most of them endangered. The genocide continues today through such acts as kidnapping native children, environmental genocide, and denial of healthy food.
Read some statistics from Pine Ridge Reservation. Call it genocide. Don't let people hide it. Never forget.
Here are some ways to celebrate Indigenous Peoples' Day. My ideas include ...
Support heritage languages. If you have disabilities or other limitations and don't feel like you can make a difference, this is one way to make a BIG difference.
Explore native foodways. Enjoy some traditional recipes.
Attend a powwow. There are indoor and outdoor ones in many places.
Restore sacred species such as bison and salmon.
Advocate for the return of stolen lands. Pay rent on held lands. Either look up your nearest reservation, or identify tribes that used to live in your area and find where they are now. Most reservations have some kind of assistance fund because almost all of them are poor.
Participate in the gift economy. If you go to a powwow, listen for the Blanket Dance. The announcer will say what it's for; usually the Drum has one, sometimes other causes do too. Most places, it is appropriate to throw down money by four, even if it's just a dollar bill at each compass point. Watch the other dancers and try to follow along, but generosity matters more than physical skill in this one.
Buy arts and crafts from native artists when you can.
Listen to traditional music. Styles vary from mellow to hyper, there's something for everyone.
Read books by and about Native Americans.
Pass the word about cultural trauma and trauma-informed care. Practice cultural fluency. When dealing with tribal folks, understand that they may be touchy or panicky about some issues for historic and current reasons. In cases of impaired consent, the principles of assisted decision-making may help someone make better choices than they could manage alone. It's not something you ever really "get over." My county recently banned public potlucks, which drives me bugfuck because it's happened before. That's after they ran off our local powwow some years back. I don't pretend to be polite about this shit.
Donate to Native American charities. Friends of Pine Ridge provides a variety of necessities such as school supplies and utilities. That's "my" reservation, where I have some very distant kin-by-marriage. Native American Aid has a page for Rocky Boy's Reservation if you're enjoying the T-American version of that setting. The Language Conservancy supports revitalization efforts. The Cultural Conservancy has multiple programs for native foodways, media, and other topics; see their donation page. North American Traditional Indigenous Food Systems deals in historic foods and food sovereignty. Native American Rights Fund is a legal organization.
If you enjoy aspects of Native American culture, if you live on Turtle Island, if you like my writing which touches on these ideals -- give something back.