Square kilometer
A square kilometer (km2) was a unit of area equal to one kilometer by one kilometer . One square kilometer was equal to 1 million square meters. This unit of measure was used primarily on Earth and within Federation.

Comparative list of area 
 While search for Malcolm Reed's missing communicator on Gosis' species homeworld in 2152, they were initially at a loss of where it could be because they had covered so much ground during their initial away mission. Fortunately, Hoshi Sato amplified its power signature with an inverse carrier wave and were able to isolate its location to within an area of 2 square kilometers. ()

 When the shuttlecraft that Chakotay and Seven of Nine emergency transported from  crashed into the energy barrier on Ledos in 2378, Seven found that the shuttle's debris was scattered over several square kilometers. ()

 During Tuvok's initial exploration of the interior of the Nyrian biosphere vessel that they were held prisoner aboard in 2373, he discovered ten s, like the one the crew of  were being held in, that were spread over approximately 4 square kilometers, and surrounded on all sides by wilderness. ()

 The zoo area located within the Lactran city on Lactra VII where Kirk, Spock and McCoy were taken by the Lactrans, was identified as being 5 square kilometers. ()

 The unidentified penal moon discovered in the Gamma Quadrant in 2369, was discovered to have humanoids localized in 12 square kilometers on the moon's surface. ()

 An area of 30 square kilometers was determined to be affected by tricyanate contamination on the planet Beta Agni II in 2366. The contamination, found at levels approached 42 parts per million, was later determined to be intentionally caused by Zibalian trader Kivas Fajo. ()

 Debris from the high speed impact of a Ferengi cargo ship that crashed in the Hanolin asteroid belt in 2368 was spread over an area of 100 square kilometers. ()

 During the late 19th century, Greater London was hundreds of square kilometers in size. Knowing this fact, Dr. Katherine Pulaski was marveled by the holodeck's level of size and sophistication in recreating the city. Data reminded her that the holographic version of the London they were observing was "no larger than the holodeck, of course, so the computer adjusts by placing images of more distant perspectives on the holodeck walls." ()

 While preparing to search for a missing research team on Tilonus IV in 2369, William T. Riker noted that the building where they located was in the southwest quarter of the city, which itself covered over 200 square kilometers. He added, "That's a lot of land for one man to cover. I guess I'd better pack an extra pair of boots." ()

 During the 's visit to Excalbia in 2269, the Excalbians created an area of approximately 1,000 square kilometers of a completely Earth-like environment on the planet's surface, so as to allow James T. Kirk and Spock to beam down. ()

 The energy barrier erected over the Ventu region of Ledos spanned thousands of square kilometer in area. ()

 The destruction caused by the explosion in 2374, caused by an unstable Omega molecule created by Allos' species included an area of over 300,000 square kilometers. The explosion destroyed their research facility located on an M-class moon inwards from their homeworld in the Delta Quadrant. ()

 The interior surface area of the Dyson sphere discovered by the  in 2369 was found to be over 1016 square kilometers, the equivalent of more than 250 million class M planets. To completely scan the interior surface would have took the Enterprise seven hours to complete. ()

 In the planetary file for Draygo IV, it is listed that the planet's polar region was 33.57 square kilometers. ()

 In the planetary file for Vacca VI, it is listed that the planet's polar region was 24.68 square kilometers. ()

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Measurements