I had posted several strange cases with Royal Gazette announcements here before, or to be exact most of them were missing announcements on things which normally is found in the Gazette. In order to test out the question system, I posted the case of the two missing minor district creations from 1978 there. Unlike all other minor districts created in 1978 (or any other year since at least the 1950s), the creation of Khao Suan Kwang in Khon Kaen province and Plaeng Yao in Chachoengsao are not found in the Gazette database. As I knew the second one happened in October, I even tried to download all the PDFs from October in order to find if it might be wrongly indexed, or a non-indexed PDF could be downloaded, but no success at all.
So I posted the question in English, only to created a correct caption my Thai was enough. And I got an answer
ไม่ปรากฏประกาศจัดตั้งกิ่งอำเภอแปลงยาว และกิ่งอำเภอเขาสวนกวางในเว็บไซต์ราชกิจจานุเบกษา ขอได้โปรดสอบถามกรมส่งเสริมการปกครองส่วนท้องถิ่น ซึ่งเป็นหน่วยงานที่เกี่ยวข้อง ว่ามีประกาศเรื่องดังกล่าวหรือไม่ หมายเลขโทรศัพท์ 02 2419000Though I would believe the Department of Provincial Administration would be better to ask - DOLA is responsible for the municipalities, whereas the districts as central administrative entities are under DOPA - at least I now don't have to try to search it anymore in the database.
The announcement to create minor districts Plaeng Yao and Suan Kwang are not on Royal Gazette website. Please ask the Department of Local Administration which is the agency involved whether it has the previous mentioned announcement.