The flip side of the crowded destinations. Or times of the year to see the best places.
My bil just got back from the Canadian Rockies. Breathtakingly unbelievably gorgeous. Other than Banff, I didn’t see many people in his pictures.
Also the National Gallery in Washington DC has a Da Vinci. Hey it’s not the Mona Lisa but it’s close and there weren’t the big crowds around it.
Lake Superior.
Lake Superior is amazingly beautiful. I’ve only seen it from the US side but I’m sure the Canadian side is very nice also.
A few years ago we were in Vermont looking at colleges. I had the big idea to go see Calvin Coolidge’s childhood home. It was out in the middle of no- where. We got there and it wasn’t open yet for the season. (It was April).
So we just rode around a bit rarely seeing any cars. Eventually we came upon a Brewery and restaurant that had a roaring fire and tours. We look back on it fondly.
We also did a mountain biking trip in West Virginia. The Greenbriar River trail, with camping and a steam locomotive ride in Cass WV. Very quiet.
The Painted Desert and Petrified Forest in AZ. We saw about 10 other people total.
A little European country a few seem to have heard about. Moldova. Good food, nice wine, great people. Interesting places including an old cave monastery and an underground winery with the largest cave cellar in the world.
Northern European countries in winter. 
Berlin in early December when the Christmas markets are already open but the tourists are not there yet.
Seattle in January!
The Blue Ridge Parkway in June was so relaxing. No traffic and the rhodies were in full bloom.
Great thread @deb922 !!!
We were in Brussels in December, and it was great. Christmas markets were all set up on the square, but there were no crowds at all. Same in Bruges.
A few years back in early December, I wasted a whole day at Ka De We in Berlin just looking at the Christmas decorations! The giant store was pretty much empty.
Ireland in October was wonderful. No crowds at Blarney Castle and Newgrange was manageable.
Iceland. Unless you are in the Golden Circle or at the Blue Lagoon, it feels utterly tranquil and untouched.
Quebec City, Vieques (Puerto Rico), St. John (USVI), La Rioja (Spain), and Italy’s Lakes Region are enjoyable and not overrun with tourists.
The upper peninsula of Michigan.
My sister and her family travels to Europe for Thanksgiving every year and there are no crowds. She’s a school teacher and one of her kids is still in college, so they don’t have a lot of options for travel when school is out, but Thanksgiving week is working well for them.
S2 was in Moldova in May. Really liked it.
Mesa Verde NP – a real gem, enough out of the way to not be as packed as other national parks. Really interesting archaeology.
The Baltics – Riga and Vilnius are not as touristy as other cities (even in August), and once you get outside the city, the countryside is gorgeous. Tallinn was also stunning, but the cruise industry seems to drive more of the economy than any other place we visited there. They are all on the Euro, but COL is very low.
Northern British Columbia – went to a little town called Ucluelet. On the water, best scallops and sushi I’ve ever had, far removed from the hordes.
Icefields Parkway north from Banff. Stunning mountain views around every corner and most of the tourists go to Banff/Lake Louise.
Ireland in late September – things were not yet shut down for the season, but the crowds had gone home. Had ten days of glorious weather.
Belfast was very interesting and accessible.
Amsterdam in February. Off-season and it was cold and damp, but it made for perfect museum weather – and oh, there are so many museums to visit!
Doubtful Sound, South Island of New Zealand – it’s kind of the counterpoint to Milford Sound. The views are different, but it takes two hours on a boat and a bus to get to Doubtful, so you are truly in the middle of nowhere. Actually, a lot of NZ is in the middle of nowhere, esp during shoulder seasons.
But all those yoopers… ;))
Parts of Norway. We went to Flam -which was busy with cruise ship traffic but did an excursion to a near by fjord that was really quiet. We went kayaking and it was wonderful.