If we were to hang a map on the wall and put a tack in all the places I've either visited, climbed or hiked, there would be some "blank spots" on it with few or no tacks. It would be different for every person.
Anyway, here are my blanks spots for the western United States highlighted in red:
The orange dots represent the places I have lived either permanently or for extended periods of time on projects.
Outside the red highlighted areas, there aren't any large areas that I haven't visited, climbed or hiked something. I didn't mark anything east of the yellow line because I am not as interested in that part of the country other than a few areas such as (for example) winter ascents of peaks in the Presidentials in New Hamshire and around Katahdin in Maine or Maybe a winter ascent of Eagle Mountain in Minnesota and a late summer/early fall trip to the Boundary Waters to name a few.
Anyway, the "blanks spots" I have highlighted aren't areas that I have no interest in (the exact opposite is true), but are areas that I haven't gotten to yet.
Where did the "blank spots" come from?
I've wanted to climb peaks in places like Glacier, Bob Marshall Wilderness, the northern Bitterroots (I have climbed peaks in the southern portion), Cabinet Mountains, etc., but in recent years (just over a decade now), with rare exceptions I can only get time off in the winter months (or at least the cooler half of the year) and even on the rare exceptions that I do get any time off in summer, it's for only a week. Before the last decade, I could get more time off in summer, but never made it to Northern Montana/Northern Idaho and Southern Oregon/Northernmost California. I guess I haven't desired it enough to make a winter trip.
I do want to climb some peaks in the Black Hills/Devils Tower in the winter though, I just haven't quite got around to it yet.
Anyway, the blank spots in southern Arizona and the corner of Western Texas may be surprising since I can get time off in the cooler half of the year. The only reason that I haven't been to Southern Arizona is because I like the northern half of Arizona so much that I haven't made it past the northern half!
Hopefully some day, I'll be able to visit the remaining areas that I don't know so well.
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Where are you're "blank spots" in the US? I'm sure we all have them.