Shortly before he died, Brigham Young discussed Cumorah in a special conference in 1877. He said,
"I relate this to you, and I want you to understand it. I take this liberty of referring to those things so that they will not be forgotten and lost."
[See the full excerpt from his discourse below.]
Despite his efforts, Brigham's fear was realized. His prophecy that these things would be forgotten and lost has come to pass.
In our day, Latter-day Saints never learn what Brigham Young, Joseph Smith, his mother Lucy Mack Smith, Oliver Cowdery, David Whitmer, Heber C. Kimball, Wilford Woodruff and other contemporaries of Joseph Smith said about Cumorah.
No one who relies on the Saints book, volume 1, to learn about Church history knows anything about Cumorah. Regarding Cumorah, that book creates a false narrative present because in Joseph's day, everyone knew Cumorah was not merely the site of Moroni's stone box that contained the abridged plates, but also the site of the repository of Nephite records and the same hill called Ramah by the Jaredites.
In Joseph Smith's day, every Latter-day Saint knew about Cumorah/Ramah.
-Oliver's account (Letter VII) was published in the 1835 Messenger and Advocate.
-Joseph had it copied into his journal as part of his life history, where everyone can read it today in the Joseph Smith Papers.
http://www.josephsmithpapers.org/paper-summary/history-1834-1836/90
-Joseph encouraged people to republish Oliver's account. In 1841, Benjamin Winchester republished it in the Gospel Reflector.
-Parley P. Pratt republished it in the Millennial Star.
-Joseph's brother Don Carlos republished it in the Times and Seasons.
-Joseph's brother William republished it in The Prophet (a New York newspaper) in 1844.
-Joseph's nephew, Joseph F. Smith, republished it in the Improvement Era in Utah.
Oliver's explanation about Cumorah/Ramah was included in lesson manuals, books, articles, etc. It was discussed in General Conference as recently as 1975.
Today, apart from historical references such as the Joseph Smith papers, Cumorah/Ramah has been erased from the historical content such as Saints and media produced by Scripture Central.
But Latter-day Saints who are "engaged learners," who are not "lazy learners" who rely on scholars to tell them what to think, but are "learners who act" continue to learn what the prophets have taught about Cumorah.
For more info, see https://www.mobom.org/church-history-issues
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Discourse by President Brigham Young, delivered at a Special Conference Held at Farmington, for the Purpose of Organizing a Stake of Zion for the County of Davis, on Sunday Afternoon, June 17, 1877.
When Joseph got the plates, the angel instructed him to carry them back to the hill Cumorah, which he did. Oliver says that when Joseph and Oliver went there, the hill opened, and they walked into a cave, in which there was a large and spacious room. He says he did not think, at the time, whether they had the light of the sun or artificial light; but that it was just as light as day. They laid the plates on a table; it was a large table that stood in the room. Under this table there was a pile of plates as much as two feet high, and there were altogether in this room more plates than probably many wagon loads; they were piled up in the corners and along the walls. The first time they went there the sword of Laban hung upon the wall; but when they went again it had been taken down and laid upon the table across the gold plates; it was unsheathed, and on it was written these words: “This sword will never be sheathed again until the kingdoms of this world become the kingdom of our God and his Christ.”
I tell you this as coming not only from Oliver Cowdery, but others who were familiar with it, and who understood it just as well as we understand coming to this meeting, enjoying the day, and by and by we separate and go away, forgetting most of what is said, but remembering some things. So is it with other circumstances in life.
I relate this to you, and I want you to understand it. I take this liberty of referring to those things so that they will not be forgotten and lost. Carlos Smith was a young man of as much veracity as any young man we had, and he was a witness to these things. Samuel Smith saw some things, Hyrum saw a good many things, but Joseph was the leader.
(1870s1877, BY Trying to ¶7 • JD 19:38)