Where can I remove a desktop in Mission Control? In Mission Control, I can add a desktop by pushing the button on the top right. 

How do I remove a desktop?

Or where in my system preferences do I look to do this?
Enter Mission Control and press Option. A close button will appear in the top left corner of the miniature views of the desktops:



Simply press the close button to delete the desktop. Notice that you can't delete Desktop 1.