Earth

"Earth" is an abandoned Gem colony planet and the location where most of the events of Steven Universe take place. Earth contains many native species, with the dominant sentient species being humans. This Earth exists in an alternate universe; while it is apparently similar, there are many differences.

History
Many thousand years before the current time in Steven Universe, Gems came to Earth and established Kindergarten. The Rebellion was fought here and Earth became the home of the Crystal Gems.

Colony Plans
As shown in "It Could've Been Great", if the colony were finished, many more structures would have been built, including 89 Kindergartens, 67 spires, and several Galaxy Warp stations. Only 5% of this was completed according to Peridot. In addition, the Earth was to be hollowed out down to the core, with large sections of the crust removed, to make the most of its resources.

Differences
There are several historical differences between Earth in the show and Earth in real life.
 * Delmarva is a state.
 * Kansas is a major hub of the movie industry.
 * The state of Pennsylvania is called "Keystone".
 * Major American cities include Charm City and Empire City.
 * Money looks different. Some coins have Gadsden-like snake symbols, or pictures of a woman resembling Pearl. $1 bills have images of an upward-pointing diamond on the left and a Gadsden-like snake symbol on the right.
 * Instead of the FBI, there is the Department of Justice: Federal Bureau. Their symbol has 12 stars instead of 13, and instead of a shield surrounded by laurels, there's a snake resembling the one from the Gadsden flag, accompanied by a waning crescent moon symbol.
 * Based on maps of the globe shown in the show, the geography of the Earth has changed.
 * The Floridian peninsula of North America is a series of small islands cut off from the mainland.
 * Panama does not seem to connect to South America through Colombia.
 * A large island and two smaller islands can be seen off the Atlantic coast of South America.
 * The land area of South America consisting of Brazil is noticeably larger than in real life.
 * The shape of western Africa is significantly altered, with what seems to be a giant river cutting into it.
 * Russia is missing a huge chunk of land area.
 * Some islands are strung out across the Atlantic between South America and Africa.
 * The nations of Sri Lanka and Japan are larger and seem to connect to Asia.
 * Vancouver Island is missing on the British Columbia coastline.
 * The Indian subcontinent appears to be misshapen and split from the Asian continent.
 * Greenland has a more irregular shape and is more separated from the mainland.
 * World War 2 never took place, though a different war might've still occur.
 * Christmas and Halloween do not exist; however, different holidays might be practice.

Trivia

 * Amethyst, unlike Pearl and Garnet, was made on Earth by the Kindergarten.
 * Rose Quartz rebelled against the Gem Homeworld in order to protect Earth.
 * Judging by Steven's measurement comments in "Novelty Backpack," this Earth still developed the Metric system of measurements.
 * In "Cry For Help", Earth is referred to as "Crystal System Colony Planet Earth".