Origin of the name "Sala Klang"

Issue 5 of the @Amphoe magazin is available online now, and probably being available in print very soon. In their section "Things you may not know about Administration" (Page 21), they quote from the book "Thesaphiban" by Prince Damrong, father of the administrative system still in use today.

However, the governor’s home differed from other people's homes in being in a highly secure area centered on the governor's home known as a chuan. As such, government business would be conducted in a large pavilion on nearby grounds outside the bulwarks surrounding the governor's residence. This pavilion became known as the sala klang ("central pavilion").

Several of these former governor homes have been preserved, and at least two of them can be visited - the National Museum in Songkhla is in the former residence of the province governor, also the Ratchaburi National Museum is in the former provincial administrative building dating back to 1922, and the former residence of the Monthon administrator is located right next to it. And there are probably many more preserved, those two are just the ones I visited.