I know that the Enterprise-E was considered one of the largest ships the Federation ever built and I know that Borg cubes are seemingly much larger than that. What are the largest ships constructed by the Federation and in the Star Trek Universe as a whole?


The largest Starfleet starship to appear anywhere on screen is the upgraded Enterprise-J briefly seen in the episode "Azati Prime". It's described as being "almost 2 miles" in length (i.e. 3.2 kilometers) as compared to Borg cubes which are approx 3 kilometers in length along each edge.

enter image description here

The single largest constructed vessel we see in the Trek TV show is the "Voth City Ship" which measures 9 kilometers from stem to stern. Other artefacts that could vie for the title of "biggest moving structure" would be the Whale Probe (70 kilometers in length), V'Ger (78 kilometers in length) or the Asteroid/Ship seen in For the World is Hollow which measures some 320 kilometers in length

As you can see, the interior of the City Ship is sufficiently large to accomodate hundreds of Intrepid-Class ships.

Voth City Ship

Within the extended Trek (book) canon, the largest ship mentioned is a "Fury Ship". These are described in "The Final Fury" as being...

"approximately two hundred and eighty kilometers long, seventy kilometers in diameter, and the pylons supporting the pods extend some three hundred kilometers from the center".

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    Beat me to the Voth. I would venture that the Dyson Sphere from "Relics" would be larger, but am unsure if that could possibly be classed as a ship. I would say no, but others might say yes. – James Sheridan Apr 20 '14 at 8:44
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    @JamesSheridan - A Dyson sphere is a "megastructure", not a ship. It's the single largest structure we see in the show if we ignore Q's energy shield. – Valorum Apr 20 '14 at 8:45
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    I wonder if Borg cubes had increased in size by the time Ent-J was built. – Xantec Apr 20 '14 at 13:33
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    @sumbuddyx - That's the "energy cloud" around it; en.memory-alpha.org/wiki/V'Ger – Valorum Apr 20 '14 at 13:44
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    For V'Ger, the size of 78km (excluding the energy cloud) comes from the novelization. However, if we take a length of 300 meters for the Enterprise, V'Ger would be then only 260 times longer than the Enterprise; which looks ridiculous small in comparaison of the many displayed features of V'Ger in the movie. Visually, in the movie, V'Ger appears to be at least many, many orders of magnitude bigger than that. In comparaison, the size of the energy cloud is an excess of 2AU or greater than 300 millions of kilometers; making a size of 78km for the heart totaly ridiculous. – SylvainL Jul 2 '15 at 8:18

The generation ship (spoilers) in For the World Is Hollow and I Have Touched the Sky is listed as being:

"an asteroid, 200 miles in diameter, that is not in any orbit but follows an independent course through the local star system"

Since the plot involves changing the course of the asteroid, I would say that that qualifies without reservation as a "ship".

Two other contenders with less stellar (heh) provenance would be the pre-Director's Cut V'Ger, which was a ridiculous (and ultimately problematic) 82 AUs in diameter (this means that it engulfs the entire solar system), or the Dyson sphere from Relics, which was two hundred million kilometers in diameter, but arguably not a ship.

In short, there are technological structures in Star Trek that are so large that they no longer resemble our conception of a "ship".

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    It was the 'energy cloud' around vger that was (variously) 82AU and 2AU wide. V'ger itself was never more than 78 kilometers long – Valorum Apr 20 '14 at 20:08
  • Great answer and you are right that it seems once an object reaches a certain size it becomes a bigger definition than a ship. – Amir Apr 21 '14 at 20:14
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    At 82 AU V'Ger would do more than "spread from earth to many of our neighbouring planets." Taking into account the fact that Pluto is 39.2 AU from the Sun ALL the planets in the solar system would be engulfed – Cearon O'Flynn Jul 2 '15 at 10:19

Seems to me that the The Doomsday Machine of TOS is a contender here. Commodore Decker, from the first ship to be mauled by it, says:

"Miles long, with a maw that could swallow a dozen starships," Decker explains that the planet killer uses a pure antiproton beam to carve planets up into rubble. He couldn't tell if it was a ship or a living organism.

This reference says that the Doomsday machine is approximately 2700 meters, about 8400 feet, just under 2 miles.

  • A cursory analysis ofthese two images would suggest that it's about two and a half miles long. It's not a ship though, it's a weapons system; en.memory-alpha.org/wiki/File:Planet_killer,_remastered.jpg + en.memory-alpha.org/wiki/… – Valorum Apr 20 '14 at 18:11
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    One problem we may encounter is a proper definition of "ship" in the Star Trek universe. I tend to agree with you, but not all people will. – James Sheridan Apr 20 '14 at 23:31
  • @JamesSheridan - The Doomsday machine is clearly a machine otherwise the episode would have been called "The Doomsday Ship" ;-) – Valorum Apr 21 '14 at 10:39
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    Are drones airplanes? Decker couldn't tell if it was a ship or a living organism, see quote. He didn't mention machine as a possibility. Of course, all ships are machines. – Wayfaring Stranger Apr 21 '14 at 11:52
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    @JamesSheridan Sure, there's lots of room for debate here. – Wayfaring Stranger Apr 21 '14 at 13:07

Balok's ship (the Fesarius) appears in "The Corbomite Maneuver"

Spock says:

SPOCK: Reading goes off my scale, Captain. Must be a mile in diameter.

but it looks a hell of a lot bigger than that when the TOS Enterprise is shown in the foreground.

enter image description here

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    It's difficult to judge scale but it's certainly huge. – Valorum Apr 21 '14 at 10:38
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    That's what she said. It certainly appears larger than most Star Trek vessels. – James Sheridan Apr 21 '14 at 12:30
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    Given that the length of a constitution class vessel is 289 meters (~0.18 miles), I'd say Spock's figure seems fairly reasonable. – ApproachingDarknessFish Aug 5 '14 at 6:33
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    Whoopsie, no metric system, Spock? – Trollwut Jul 2 '15 at 10:21
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    @TuttiFruttiJacuzzi: visually, the angular size of the largers spheres is the same as that of the saucer of the Enterprise (130m) when it is at a distance of 5000m. If the observator is itself at the same distance of 5km, then the size of these spheres would be 260m; which would give an overall size of 5200m or 3.25 miles for the Fesarius if we take a diameter equivalent to 20 spheres. These numbers are approximate but even if the Enterprise was touching the Fesarius, the size of these spheres would still be greater than 130m and the size of the Fesarius still greater than 2600m or 1.6 mile. – SylvainL Jul 2 '15 at 11:56

If we’re counting non-canon, the DS9 book Objective Bajor revolves around an invading species from another galaxy that arrived in a continent-sized generation ship described as approximately 8,000 miles long and which could only travel at impulse.

Tak frowned. "It has an unusual configuration," he agreed, "but it is not unprecedented, surely?"

"The shape, no," Garaia commented. "But the size …" She let her eyes stray back to her instrumentation. "Captain, that vessel is approximately eight thousand miles long, and the wingspan is about twelve thousand miles. We are still almost an hour from its present position at current speeds."

Tak paled, his eyes riveted to the screen. "Eight … thousand … miles?" he repeated in awe. He shook his head in disbelief. "What kind of a craft is it?" he asked.

Garaia shrugged. She was almost as awestruck as he, but she refused to allow her scientific training to suffer as a result. "Captain, the central core of the vessel is eight thousand miles long, and approximately one hundred miles in diameter. That gives an interior surface area of over two million, six hundred fifty thousand square miles. That is the size of a moderate continent."

Bored and slightly drunk though he might be, Tak wasn't stupid. "You mean that ship is some kind of colony vessel?" he asked, leaning forward and staring hard at the image in front of him.

"It would be a logical assumption," agreed Garaia. "And one probably containing several billion inhabitants."

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    I've taken the liberty of adding in a book quote and correcting the length. – Valorum Mar 19 '19 at 14:16
  • thanks! this was one of my fav DS9 stories. as is the case with many of them, it’s themes are easily applicable to the problems of our current society (In this case being about the dangers inherent to a filtering of all information through partisan lenses, and a collective abandonment of the pursuit of objective truth). – Justin Reeves Mar 20 '19 at 15:47

Possibly, the "ISS Charon"

enter image description here

Depending how you define large1 and universe2, the Terran Empire ISS Charon might satisfy your requirements.

This flagship from the Mirror Universe is described to be the size of a city, and it is said to have 450 decks; considering that the height of a single deck could be more or less 3 meters, its total height should be approximately 1350 meters, or 1,35 kilometers. Visually it seems that its length is at least four times its height, making it more than 5 kilometers long.

Even Ex Astris Scientia, based on a visual comparation to the USS Discovery, estimates the ISS Charon to be well over 4 kilometers long.

1. The "size" of a starship could be measured in length, width, an average of the main dimensions, its volume, and so on.
2. In this case, it is the Mirror Universe.

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    Smaller than the Voth ship, but certainly larger than the Enterprise-J. – Valorum Apr 16 '20 at 23:45

Well, the Voth Fortress ships are 134.5 kilometres long.


Doomsday weapon - even though it's technically not a ship, just the diameter of its opening could swallow a fleet of ships. The Dyson sphere could also qualify as the largest ship, even though it's more like a giant space station with an internal planet-like atmosphere. It was big enough to swallow fleets of ships, Borg cubes would pale in comparison. The Caretakers Array would technically count as a ship, it was the only thing in VOY series that lacked depth and dimensions. Also let us not forget the Crenim Time ship, capable of annihilating worlds from time/space its destruction never matched its size.

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    Welcome to SFFSE! Although this is a good list, you could do with a bit more formatting to make it a more readable answer. Also, do you have the specifications of these ships? There are other answers which establish the length of various craft; if you could find the dimensions of the craft you refer to, it would be easier to compare and then evaluate your answer. – Often Right Jul 2 '15 at 7:13

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