The following comes from a book entitled Glad Tidings Near Cumorah by Bruce E. Dana, 2004. Dana wrote a number of books including Mysteries of the Kingdom and The Three Nephites. Once compiled, Dana knew the evidence supported One Cumorah – in Palmyra:

Though Joseph Smith has stated that the Hill Cumorah is located in Manchester, New York, there are various people who believe that this hill is actually located outside of the United States. (Dana, p. 55)

 

Those members of the Church who believe that Joseph Smith, Jr. is a prophet of God should discredit all people who theorize that the Hill Cumorah is located outside of the United States. (Dana, p. 60)

Dana goes on to quote Joseph Fielding Smith’s fierce rebuttal (Doctrines of Salvation, vol. 3, p. 232) then says:

It needs to be emphasized that this type of thinking has been circulated and promoted for nearly fifty years. Various writings have been published to prove this theory. In these publications, various authors use geological data and photographs to support their claim. "Because this theory," says Elder Joseph Fielding Smith, "some members of the Church have become confused and greatly disturbed in their faith in the Book of Mormon. (Dana, p. 56)