Three things are inevitable: Death, taxes and noise .
That being said, there are really levels of quietness and some places are nearly silent.
Probably some of the quietest place is the desert.
Camping in the desert affords remoteness from construction and there is little sounds of nature.
Remote islands are also an excellent choice.
Currently, I am in La Digue which has apparently less than 10 vehicles on the island.
There is not much wildlife either, so I pretty much here nothing most of the day and night except other tourists talking at the beach or in restaurants.
Even then, it never gets loud here.
There are plenty of vehicle-free islands around the world which can provide a very quiet environment, specially arid ones which usually feature less wildlife.
A jungle or cloud-forest lodge gets pretty quiet from human noises but the wilderness is alive at night.
I have had several stays in the Amazon and several jungles in Central America, and I can say that there are plenty of sounds at night when trying to sleep.
Except for howler monkeys of Guatemala, a good set of ear-plugs greatly helped.
For cities, it really varies
but I had great joy in spending time in pedestrian cities in Croatia.
Dubrovnik, Korcula, Split and Zadar all have pedestrian-only centers that are much more quiet than typical cities.
So much that when I reached Zagreb, it took my a while to notice why it was much more noisy there: motor vehicles.
Also those historic cties have very little construction going on since the buildings are already densely packed and kept for historical value.
Be sure not to choose a hotel near a disco, bar or the like, since that can create quite a racket that reaches a few buildings.
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You would do worse than travelling to somewhere like Green Bank, West Virginia, which is in the middle of the National Radio Quiet Zone, where electromagnetic emissions are heavily controlled.
This means fewer cars, practically no mobile phones, no construction, no loud music (speakers bleed EM badly) etc etc.
While its a Radio quiet zone, this equates to a lot of things which make audible noise, hence my suggestion. https://en.wikipedia.org/wiki/United_States_National_Radio_Quiet_Zone
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Many cities have laws regarding noise levels, but your definition of quiet is probably a lot more restrictive than what will be written into law.
There are many areas in the world that have banned vehicles (typically electric vehicles are permitted) and there is often an overlap between 'sleepy, rustic town' and these vehicle-free zones.
While that's not a cuarantee of quiet, it may be a start.
Try checking out the list on Wikipedia .
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Speaking for the US, most, maybe all, municipalities have noise or general nuisance ordinances, however, I would not rely on this as any sort of guarantee or even expectation.
There will always be exemptions, especially during the day for normal activities such as construction or social events.
The physical location will be much greater determining factor, specifically the relative remoteness of the destination.
I have considered such vacations before and focused on the 'cabin in the woods' type location.
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Death Valley.
This ad literally says "Quiet you can feel on your skin."
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Absolutely North!
North/South Poles, Grenland, Iceland, Alaska.
Peace and quiet guaranteed.
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Assuming you want to take a several months long vacation from the noise of the city, are there cities, towns, countries even with laws that are enforced to keep things quiet? (i.e., no construction, no loud music, no idling of vehicles.)  Many places promote "peace and quiet" but do any have it written into their city's bylaws?  A Google search  comes up blank.
Possible to Travel to A Quiet Place?
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You could travel to cities with pedestrian-only centres like Dubrovnik, Korcula, Split and Zadar, or find municipalities with noise or general nuisance ordinances, but these may not guarantee quiet. One promising location is Green Bank, West Virginia, which is in the middle of the National Radio Quiet Zone, where electromagnetic emissions are  heavily  controlled. In terms of keeping things calm and quite there are a few laws that keep the peace such as, pedestrian only zones that can be found in Dubrovnik, Korcula, Split and Zadar, general nuisance laws that are inforced in most US municipalities and even national radio quite zones that can be found in Green Bank and West Verginia
Dubrovnik, Korcula, Split and Zadar all have special "pedestrain only" areas that control the overall noise out within the environment  In terms of the US most municipalities have general nuisance ordinances Green Bank and West Virginia are in the middle of National Radio Quiet zones which keep loud radio and phone music to a minimum.