See the series that Justin photographed at https://www.justinmhamel.com/postofficemurals?fbclid=IwAR2qr_A9XOpDFUZgXxrfMMRW3HmoBq80LQEDyY8M3t9f4k_A-mR4wzVya8U#1
The majority of relocated murals are in local museums or libraries. Examples of these are the murals in Borger, Texas (Hutchenson County Museum); Brevard, North Carolina (library); Enterprise, Alabama (library); Fort Pierce, Florida (City Hall); Idabel, Oklahoma (Museum of the Red River); Lamesa, Texas (community center); and Sebring, Florida (library). The most interesting location a mural now hangs is in a hotel suite in Covington, Louisiana.
All wrapped into one, it is undoubtedly the largest public art project in the US.
In 2019, the post office made a series of stamps to show some of the murals: https://about.usps.com/newsroom/local-releases/co/2019/0410-post-office-murals.htm and https://www.amazon.com/Office-Murals-Forever-Stamps-Release/dp/B07QLHJJM2
A photographer who chooses to locate, photograph, and document a specific thing, is something I've only found a couple of times that has something to do with the vehicle world, so that I feel it's part of what I blog about, but you might remember the rail car diners, roadside rest area picnic tables, and the parking lot attendee booths, so, this isn't as vehicle related in terms of post office paintings, but the ones I've selected here are the railroad and tractor paintings
There are four murals by Stevan Dohanos in the Charlotte Amalie, Saint Thomas, post office in the U.S. Virgin Islands, which are likely the only remaining New Deal–funded artworks in a United States territory.
see the following for more:
If you'd like to find some, and want to look them up by state, this wikipedia link is terrific! https://en.wikipedia.org/wiki/List_of_United_States_post_office_murals
but this one is even better! https://livingnewdeal.org/map/