Not sure exactly where this scenic photo was taken (it was found on the net). However I think somewhere in the western part of the US or Canada.
Edit, Update: This is Mount Shasta in the background. A lengthy toll line ran alongside this Alaskan highway, similarly constructed to the DBR (Defense Backup Route) line in western US during the early 1940s. Both employed a LOT of Pyrex toll-line-styled insulators. Thanks Widdo