Earth is a unregarded little blue-green planet far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy (specifically, Galactic Sector ZZ9 Plural Z Alpha). It is populated by all sorts of creatures, of which the most important are mice, dolphins and human beings, the latter of whom may or may not be descended from a race of Golgafrinchan telephone sanitisers, hairdressers, management consultants, and documentary film producers. These Golgafrinchans arrived in a space ark which crashed onto the planet about two million years before the Vogons destroyed it, and christened their new home "Fintlewoodlewix".

Though often mistaken for a planet, Earth is in reality the greatest supercomputer of all time, designed by Deep Thought to discover the Great Question of Life, The Universe And Everything (to which the answer is 42).

Earth is also home to Arthur Dent and Trillian.

The Hitchhiker's Guide To The Galaxy used to describe Earth as "harmless". After lengthy research Ford Prefect expanded the entry, which was then cut down to "mostly harmless".

Altair is mentioned briefly as one of the points of origin for the galactic civilization's "shoelace production" industry. It is indicated that the galaxy's various civilizations are largely unaware of Earth's existence, and Earth itself is considered unimportant in the grand scheme of the universe. Altair's significance lies in its connection to this particular industry rather than any detailed description of the system or its inhabitants.

Apart from being one of the closest stars to Earth's solar system, Alpha Centauri is home to both small furry creatures and a local planning department office of the Galactic Hyperspace Planning Council.

Kocab is a starsystem in Ursa Minor

Ursa Minor is home to the "great publishing corporations", such as Megadodo Publications which created The Hitchhiker's Guide to the Galaxy.

Ursa Minor Alpha hosted the Annual Ursa Minor Alpha Recreational Illusions Institute Awards Ceremony, from which a certain prize was stolen by Krikkit robots and used as part of the key to the Slo-Time mechanism surrounding planet Krikkit. Ursa Minor Beta is mostly a subtropic coastline and is, strangely, always on a Saturday afternoon, before the beach closes. It is very bright, and its capital is Light City, which is totally surrounded by water so much, the only way there is by plane. Light City contains the Lalamantine district, where it is always a cool Saturday evening instead.

Unlike what it seems, it is probably the most appalling place in the Galaxy, and as one editor said, "If you don't like Ursa Minor Beta, you don't like life," the suicide rate quadrupled.

Aldebaran, or Alpha Tauri, is a star forty-four times as big as the Sun. Its system is famous for its liquors, and the only thing left after the end of the universe is one of its sweet trolleys, and liquors, as Max Quordlepleen says. It is "great, OK", according to a chant recited by crowds outside the Sirius Cybernetics Corporation Teleport Systems factory on Happi-Werld III.

The Pleiades system is a star system where Ford Prefect hacked into the British telephone service, and left his ship connected, running up a huge phone bill.[1] Pleiadies Zeta, or Zondostina, is a star in this system. The Pleiades are also known as the "Seven Sisters".

Sesefras Magna is a huge orange gas giant which orbits Zondostina, and is home to Port Sesefron, a spaceport for Xaxisian battleships.

Epun is one of Sessefras Magna's moons. It is blue, small and cold.

Betelgeuse Five is the home planet of Galactic President Zaphod Beeblebrox and his semi-cousin Ford Prefect. Betelgeuse Seven was the birthplace of Ford Prefect's father, who was the only survivor of the Great Collapsing Hrung Disaster of Gal./Sid./Year 03758, which wiped out the old Praxibetel communities on the planet.

Orion Beta

Orion Beta is a star system noted for its madranite mining belts. At a hyperspace port serving the mining belts, Ford Prefect learned to play a drinking game described as a form of psychic arm wrestling and involving telekinesis. Given the joys of intoxication and the graphic nature of the forfeit, Ford played to lose.

Judging by the name, this location in real-life may be Rigel, which is also known as Beta Orionis.

the Vega system is mentioned as a location in the context of a starship's journey. However, there is no specific information provided about Vega itself or any associated planets or inhabitants in the book series. The mention of Vega serves primarily as a passing reference rather than a detailed description.