Pass, after which we descended into the plain or valley of Kirta, an extensive plain more than 20 miles across, and almost circular in shape, the mountains rising to a considerable height all round it.
Page 134)] Sun spots are, as a rule, some thousands of miles across.
In North America there are terranes scores of hundreds of miles across in various directions and hundreds and even thousands of feet thick that have been formed in the manner just indicated.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "miles across" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.