It is the lowest of the three LDS kingdoms of glory. This kingdom will not be visited by Heavenly Father or Jesus but will have access to the Holy Ghost. This will be the final destination for the irreligious and immoral people, even professing atheists.
“The people who live in the telestial kingdom are those who did not accept either the gospel or a testimony of Jesus, either on earth or in the spirit world. They will suffer for their own sins in spirit prison until after the Millennium. Then they will finally be resurrected. While on this earth, they were liars, thieves, murderers, false prophets, adulterers, and those who ridiculed sacred things. They were the people who accepted the beliefs of the world rather than the teachings of Jesus. Many people will live in this kingdom.” (Gospel Fundamentals, Chapter 36: Eternal Life.)