I've never been anywhere quite like it. My friend once described it as "an art piece that uses museum curation as its medium" and that's the best description I've come across. To get an idea of what that means, understand that it's fully laid out as a museum with exhibits featuring various objects and artifacts and expositions thereof but these exhibits wildly vary between truth and fantasy. Some are showcases of real, if niche, cultural practices and some are histories of entirely fictional figures that are nevertheless compelling and beautiful.
The creator was awarded a McArthur grant in 2001 and I feel it was more than deserved.
Another strong recommendation for this unique place. I visited soon after its 1988 opening. The museum was so off the grid and unknown that early visitors like me received personal guided tours of unlimited duration from its founder/creator, David Hildebrand Wilson.
It was wonderful. Scintillating. Alas, that was in the late 1980s and I haven't been back, though from the photo in Wikipedia its kind of derelict/dumpy entrance looks like it hasn't changed at all.
If you read "Mr. Wilson's Cabinet of Wonder: Pronged Ants, Horned Humans, Mice on Toast, and Other Marvels of Jurassic Technology," Lawrence Weschler's superb 1995 book about the museum with extended interviews with Wilson, you will find it hard not to want to visit.
As someone in the process of building a niche museum about hyperlocal archaeology and history in my Philadelphia neighborhood, the timeliness of this post is excellent.
Speaking of, The Amsterdam Pipe Museum is fantastic. On the surface, it seems like some kind of stoner side show, but the people running it are very, very experienced archaeologists, and we ended up buying multiple books from them on the topic of pipes. Trained archaeologists in Philadelphia will look at a clay pipe and say "That's Dutch" but these guys are like "That's from Gouda, and was probably owned by a farmer"
It's not a Niche Museum but the Reykjavik Art Museum & Reykjavík Art Museum Kjarvalsstaðir both are amazing and worth a visit too, neither are far away in Reykjavik from the Phallological Museum.
Reykjavik is quite nice to visit! It's similar to Ballard, WA, where we have a somewhat niche Nordic Heritage Museum that very nice as well.
The Rosicrucian Egyptian museum is a pretty neat museum in San Jose. I remember going several times as a kid, really cool place with a remarkably large collection. Only relatively recently did I dig into who the heck the Rosicrucians are, and that's a wild deep-dive in of itself which probably should feature somewhat in the museum. Basically, in the early 17th century, a couple of essays were published describing this ancient order of mystics called "The Brotherhood of the Rosy Cross" which protect secret and powerful knowledge. At some later point, a bunch of societies popped up that claimed to be descended from the "original Rosicrucians" (of which not only is there no evidence of ever existing, but the guy who presumably wrote the first essays about them published an essay about how he made them up as a bored 16 year old). Today, the largest such group is headquartered in San Jose, and run a pretty sick Egyptology museum.
The Toy Museum of Munich is pretty cool and it is near a major tourist site in Munich, Germany. My wife and I went in to kill an hour while we waited for others and it was really nice. Covers 4 centuries of toys and toy evolution.
If you're in to some combination of American cultural history, pop art, or graphic design / typography, you might get a kick out of the American Sign Museum in Cincinnati, OH. It's a gem: https://www.americansignmuseum.org/
Aside: I wish the Museum of Holography in Chicago hadn't imploded. It was immensely cool.
Aside aisde: I love that this site has an RSS feed.
There is a Cuba museum in my hometown, Tuxpan, Veracruz Mexico. History goes that, Fidel Castro, after exiling, organized and trained men and then sailed from the port to Cuba, ultimately this starting the Cuba revolution and his regime's start.
Not sure Stonehenge qualifies as "niche". Anyway ...
If you're ever visiting the Lake District, NW England, I recommend the unexpectedly interesting Pencil Museum in Keswick. Graphite was first mined nearby and when it was realised it could be used for pencils, it became extremely valuable, requiring armed guards for its transportation. Thus Keswick claims to be the birthplace of the modern pencil.
They have 'Big Roy', one of the largest tractors ever built. It came into existence during a progressively competitive era of building super large tractors in the 60s. They also have several operating steam tractors and a workshop that restores them.
My friend from school days, who is into a digging up lot of WWII stuffs, have a museum in a remote corner of India. Backed by Japan, and the local government, it is located near to other Japanese related location in Imphal, Manipur (INDIA).
Here are some pictures I took while visiting it some time before the official opening. I think I got some of the Indian Currency printed by the Japanese during the war. I might also have copies of some videos from during that time (I think the 40s-50s).
Corning NY has a Glass museum that is run by the Corning Glass Company (company that makes iPhone glass). Which is pretty cool, if you are ever in that area.
It's only museums I've visited myself. I actually do have a draft entry in the works about the Glass Flowers at the Harvard Natural History Museum, I should finish and publish that!
I think the site is compiled by one person. If you look at the map (https://www.niche-museums.com/map) it's heavily biased towards the southern UK and the SF Bay Area.