The Book of Mormon names 170 geographical locations and there are well over 100 which form part of the storyline. The named places in the Book of Mormon are also of varying types, including lands, cities and areas.
How long would it have taken Joseph Smith to have come up with the names of all these places? Why would he include over 100 places in a storyline of 500 pages? Why include so many places if each one would only add to the complexity of the book?