In order to delete a board, you'll need to close the board first. Closing a board is similar to archiving a card—you can leave it in your "Closed Boards" list if you think you might want to use it again some day, or you can delete the board permanently once it's closed.
I have been looking around for 2 hours now and for the life of me CYN NOT CLOSE a board or delete a board. I simply do not find the option do do this (there is no m enu for it).
?????
Werner
In the menu options -> Close Board
Look at the image
Cheers