The most overgrown areas Canada-U.S. border include:
The mountainous terrain separating British Columbia, Washington and Idaho.
The forested areas separating southern Quebec and New Brunswick from the New England states.
Rocky Mountain sections of Glacier National Park in Montana and Waterton National Park in Alberta.
Theboundaryrunningthroughthe wilderness of the Yukon from Alaska, where work crews have encountered thorny vegetation grown four metres high in places.