The ground scale is 1/1000. The board is about 1m by 1m so it represents 1 sq km. The buildings are by brigade models and are from their 2mm/ 1/1000 range. The bridge is scratch built to the ground scale based on what info I could find online.
The figures I’ll be using to game on it though will be 6mm, based on a platoon per stand on 32 by 25mm bases.