The demonstration was part of a movement called "Idle No More" that's swept across Canada. It protests legislation that many First Nation people say threatens their land and water.
The protest closed the border crossing for several hours. Despite a history of clashes with border officials, the march was a peaceful, family affair, full of drumming and singing.
Cook also educated listeners - and producers...
Aaron Atahontsion and other men with hand drums moved to the front.
"Our people, we have drums and we have rattles. We use the vibrations of all these rattles and drums to send out to the universe. And we also sing our songs are kind of an interpretation of the drum beat in our heart."
Idle No More protests like this one have been held all over Canada, and in several other countries. There's deep opposition among First Nations people - that's a term that loosely describes the indigenous peoples of Canada, generally not including Inuit or Metis people - to Prime Minister Stephen Harper's omnibus budget bill. They say it could open reserve land to private developers and violates aboriginal treaty rights.
Joe Verdugo organized this march via Facebook and Twitter. He says Idle No More is bringing all indigenous people together.
"This is not just about us, either… As [aboriginal] people, we're put here in this earth to protect the land and that's what we're gonna show today."
Parents pulled their kids in wagons across the first span. Elders caught rides on four-wheelers. A woman burned ceremonial sage and the smell carried over the whole march.
Several hundred more marchers joined in on Cornwall Island, which is part of the Mohawk Nation territory of Akwesasne, to continue over the second span.
Carolyn Francis is a social worker on Cornwall Island.
"All of her brothers and sisters across Indian Country are in support of her, also. We need to have the Canadian government listen to us that we are still here and we are still going to make them stand up to the treaties that were written, that were done a long time ago."
Harper has said he respects people's right "to express their point of view peacefully", but he had resisted meeting with First Nations leaders about the Idle No More concerns. But last Friday, he agreed to meet on Jan. 11, 2013.
That lent a small whiff of victory to the march. When it got to Cornwall, Canadian customs officers simply smiled and said good morning as marchers poured through the border crossing.
Margie Skidders, a retired BOCES teacher, says it was powerful.
"Dancing in an unusual place, and so, yeah, it was really powerful. It was just powerful walking over the bridge with no cars and to be able to enjoy the scenery and think, this is where we live. This is what we're protecting."