They said Lower Post was one of the most notorious residential schools in Canada. It now serves as the administration offices for the Daylu Dena Council.
Tahltan Nation president Anita McPhee's mother and five uncles attended there and she said they were haunted by it.
"It could be just looked as just a building, but it's not. It's the history, it's the energy, it's everything and it needs to be destroyed."
Organizers of the gathering said the next step is to get the building replaced by a new, proper administration building for the Kaska community.
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