There are times in V Rising when you realize that the borders you originally claimed need to be removed and added somewhere else. The game seems to want to keep you from removing borders without explaining why. But there is a way to remove those borders.
To remove a border in V Rising, press the B key to go to Build mode, then hold down Spacebar on the border tile you want to remove to dismantle everything. Ensure you do this to the other tiles around it as well. You can now remove the border tile by hovering over it and pressing Dismantle (Spacebar) again.
Related: How to get glass in V Rising
Do I have to clear out the tiles around border tiles in V Rising?
Removing a border tile requires players to first remove everything within the tile and everything up against the tile. Players must remove all walls, floors, and objects up against the tile. Essentially, the tile you remove and all adjacent tiles must be cleared. This is inconvenient, but there is currently no way around it.
As time goes on, this becomes less necessary, as you can use more border tiles and won't need to ration them because you'll slowly gain more space. Although, as you can see from the above method, it is better to plan everything before placing your border tiles.
How to move your castle territory borders somewhere else in V Rising
If you wish to move your castle outright, along with all of its border tiles, you will have to remove your castle heart entirely. As our guide on How to move your Castle Heart in V Rising states, you'll have to dismantle everything within your borders once that has been completed.