Announced in the Royal Gazette on July 31, some area previously under the supervision of the subdistrict administrative organization (TAO) Si Songkhram was reassigned to the subdistrict municipality Si Songkhram, both in the subdistrict Si Songkhram, district Si Songkhram, Nakhon Phanom province.
In fact, there were two announcements, the first one for the change of the TAO titled ประกาศกระทรวงมหาดไทย เรื่อง องค์การบริหารส่วนตำบลศรีสงคราม อำเภอศรีสงคราม จังหวัดนครพนม แยกพื้นที่บางส่วนไปรวมกับเทศบาลตำบลศรีสงคราม อำเภอศรีสงคราม จังหวัดนครพนม, and the second for the municipality titled ประกาศกระทรวงมหาดไทย เรื่อง เปลี่ยนแปลงเขตเทศบาลตำบลศรีสงคราม อำเภอศรีสงคราม จังหวัดนครพนม. Strangely, this change apparently wasn't discussed in the board meetings unlike others. This second announcement also includes a map, which helped me to identify the municipality office on Google Earth and thus pinpoint this posting to exactly that location. Sadly the TAO office isn't shown in the map, and not marked in any other maps I know of. And their website srisongkham.org apparently expired not too long ago.
Comparing the map with the one in the 1956 announcement on the creation of the sanitary district Si Songkhram (Gazette), the precursor of the municipality, it shows that the town has grown quite a lot, the original municipal area included gardens, fields and forests around the actual settlement which are now covered with houses, and only shows a subset of the streets it has today. However it seems to be badly aligned, because if the arrow in bottom is supposed to indicate the north direction, the boundaries would be exactly in east/west and north-south direction, as well as the main streets, which isn't the case in real.
I now also found out how the coordinates of the reference points (หลักเขตที่) are to read. For example the point in the northwestern corner, VE ๒๐๔๕๐๘ means the UTM coordinate 48Q4204 19508. With this and the maps in the two announcements I have drawn the map below to give an approximate idea. Interesting to note - the municipality office is located right at the boundary of the old municipal area. The added areas are both to the east and the south.
View Si Songkhram in a larger map