The 24th century, defined in the calendar of Earth as being from 2301 until 2400, was a period of great conflict and political upheaval between the various races and organizations of the Milky Way Galaxy. In the latter half, the Federation makes contact with several new species and civilizations, including powerful new races such as the Q, and other lesser races such as: the Ferengi, the Dominion, and the Borg, the latter two of whom attack the Federation on several occasions. The Romulan Star Empire enters a second period of isolation, lasting approximately fifty years, from which they emerge far stronger than ever before. The Borg attempt to assimilate Earth twice, first in 2366 and again in 2373. The latter year also sees the beginning of the Dominion War, which ends in 2375, with several of the major powers of the Alpha and Beta Quadrants joining together to defeat the Dominion.
In addition, the Federation makes its first explorations of the Delta and Gamma Quadrants during the latter half of this century. Also, in 2387, the Romulan system is destroyed by a supernova which, due to the actions of Ambassador Spock and Nero, ultimately leads to the creation of an alternate reality.
- After the Tomed Incident with the Romulan Star Empire, the Federation signs the Treaty of Algeron, promising no research into or use of any cloaking devices. (TNG: "The Neutral Zone", "The Pegasus"; ENT: "These Are the Voyages...")
- At the Battle of Narendra III, the Federation vessel USS Enterprise-C defends a Klingon colony against Romulan attackers. Regarded as an honorable act, the incident cements the Federation-Klingon alliance. (TNG: "Yesterday's Enterprise")
- A subtle attempt by parasitic beings to take full control of Starfleet and to prepare for an all-out invasion of the Federation is discovered and thwarted. (TNG: "Coming of Age", "Conspiracy", "The Drumhead")
- After making first contact with the Borg in 2365, a Borg cube attacks the Federation but is destroyed in Earth orbit after the Battle of Wolf 359. Later that year, Klingon Chancellor K'mpec is killed and succeeded by Gowron. His position is quickly challenged but eventually affirmed in the brief Klingon Civil War against the Romulan-influenced, but ultimately inferior, House of Duras. (TNG: "The Neutral Zone", "Q Who", "The Best of Both Worlds", "Reunion", "Redemption")
- The Bajoran Wormhole is discovered, representing a secure link between the Alpha and Gamma Quadrants. (DS9: "Emissary")
- The Federation signs a treaty with the Cardassian Union, establishing a Demilitarized Zone along their shared borders. Several Federation colonists opposed to the treaty, as well as several sympathetic Starfleet officers, organize an armed resistance called the Maquis, carrying out a series of attacks on Cardassian military targets. (TNG: "Journey's End"; DS9: "The Maquis, Part I", "The Maquis, Part II")
- The USS Voyager, the Maquis ship Val Jean, and (unbeknownst at the time) the USS Equinox are pulled into the Delta Quadrant by an advanced being known as the Caretaker. Effectively stranded seventy-five years from Federation space, the Voyager crew, augmented by the Maquis and some Delta Quadrant inhabitants, engage in extensive exploration of the quadrant during the journey home, though Starfleet does not learn of this until 2374. (VOY: "Caretaker", "Message in a Bottle", "Equinox", "Equinox, Part II")
- After the Dominion and the Founders are discovered in the Gamma Quadrant in early 2371, the Federation condemns an attack by the Founder-infiltrated Klingon Empire on the Cardassian Union. A few months later, a Founder-Changeling bombs the Antwerp Conference between the Federation and the Romulans, giving rise to an attempted but failed coup d'état against Federation President Jaresh-Inyo. Near the end of that year, the Federation's and Klingon's old dispute over the Archanis sector escalates, leading to the Klingon's withdrawal from the Khitomer Accords. (DS9: "Homefront", "Paradise Lost", "The Way of the Warrior", "Broken Link")
- After the Founder infiltration of the Klingon Empire is discovered and the Cardassian Union joins the Dominion, the Khitomer Accords are reinstated. In the midst of these events another Borg cube attacks the Federation, but is destroyed near Earth in the Battle of Sector 001. Later that year, the Dominion conquers Deep Space 9, igniting the Dominion War against the Federation-Klingon alliance. (DS9: "Apocalypse Rising", "By Inferno's Light", "Call to Arms"; Star Trek: First Contact)
- After losing Deep Space 9 to the alliance again, the Dominion conquers Betazed. Later that year, the Romulan Empire turns the tide of the conflict as it declares war against the Dominion. (DS9: "In the Pale Moonlight")
- The Breen Confederacy allies with the Dominion and launches an attack on Starfleet Headquarters on Earth. Shortly after, Gowron is killed and Martok becomes the new Klingon Chancellor. Near the end of that year, with the help of the Cardassian Rebellion, the alliance manages to repel the Dominion forces, finally capturing Cardassia Prime and ending the Dominion War with the Treaty of Bajor. (DS9: "'Til Death Do Us Part", "The Changing Face of Evil", "When It Rains...", "Tacking Into the Wind", "What You Leave Behind")
- The Romulan Empire is taken over by Praetor Shinzon as the head of a Reman coup d'état. After a false peace offer to the Federation, Shinzon is killed in his attempt to wipe out all life on Earth with thalaron radiation. Shortly after, the Federation begins talks with the new Romulan government. (Star Trek Nemesis)
- Rogue synths launch an attack on Mars, destroying the Utopia Planitia Fleet Yards and setting the planet ablaze. (ST: "Children of Mars") Starfleet abandons plans to aid the evacuation of the Romulan system. The United Federation of Planets places a ban on synthetics. Admiral Jean-Luc Picard resigns his commission in protest. (PIC: "Remembrance")
- Jean-Luc Picard is sought out by a young woman named Dahj after her boyfriend is killed. It is revealed that she has a twin sister and they are androids. Zhat Vash agents have been embedded in Starfleet. The Romulan Free State has been researching a derelict Borg cube. (PIC: "Remembrance", "Maps and Legends")
- Yor travels from the Alternate reality to the future of the prime reality. (DIS: "Terra Firma, Part 1")
|23rd century||Timeline||25th century|
24th century productions
- ENT: "These Are the Voyages..."
- Star Trek: The Next Generation
- Star Trek: Deep Space Nine
- Star Trek: Voyager
- Except for "Living Witness"
- Star Trek films:
- "Remembrance" (Season 1)
- "Maps and Legends"
- "The End is the Beginning"
- "Absolute Candor"
- "Stardust City Rag"
- "The Impossible Box"
- "Broken Pieces"
- "Et in Arcadia Ego, Part 1"
- "Et in Arcadia Ego, Part 2"
- "The Star Gazer" (in part) (Season 2)
- "Watcher" (in part)
- "Two of One" (in part)
- "Monsters" (in part)
- "Hide and Seek" (in part)
- "Farewell" (in part)
- Star Trek: Lower Decks
- Star Trek: Prodigy