Large swaths of Canada are similarly unexplored except by aerial survey. There was a story about the world’s largest beaver dam on HN earlier this year [1] and how remote it was.
Since it’s mostly bogs, peatlands, and boreal swamps, it’s practically impassible to humans except occasionally when the water level rises enough to support a boat but even then the dam was only accessible by luck. The water is just too cold for humans to survive going deep into the wilderness, even with modern clothing and tech.
