Deleting rows from Tile Map Node

I laid out a pretty large tile map node in the normal way for the U.S. Left to right, top to bottom, and found out there is too much space vertically. Too many rows. If I change the map size, it removes rows from the top and not the bottom! Like that Google Cheesebuger with the cheese on the bottom, it makes sense in a different culture, but not ours. So how can I move everything down 10 rows, or remove rows from the bottom, or something else so I can reduce the map size and clip the scene to just the right amount of vertical space?