Jovian Settlements:
The space around Jupiter has become one of the more heavily populated portions of Human space. It is estimated that there is as many people in the Jovain system as on Earth between the various Belter and corporate interests in the Trojan asteroids, the settlements on Europa and Io, and the Hydrogen mining settlements in the upper Jovian atmosphere. The Jovian system is an encapsulated political entity with multiple 'Regions' all of which lie under the umbrella of the Confederation as a single political State.
In many ways the Jovian settlements are the greatest political rival for Mars within the Confederation. The rest of the States are smaller and politically dependent on Mars for some sort of support.
In total, about 250,000 humans live in the Jovian system. The Jovian State is comprised of 4 administrative 'Regions': Europa, L4, L5 and Io.
All of the members of the Jovian State maintain the Jovian militia; a small navy, marine force and police that are trained in urban combat.
The most common language in the Jovian state is AmEnglish, other than on Europa.
Jupiter itself is considered property of the Jovian Settlements. However, no one actually lives on Jupiter. Instead there are innumerable corporate interests engaged in Hydrogen and Deuterium mining form the upper atmosphere of the planet. These corporate interests must conform to ICC and Jovian regulations for operation. Most important of these installations is the ICC refilling station in geostationary orbit. This station provides Hydrogen by the millions of tons per year to commercial and military interest for a nominal yearly fee. The ICC station can support up to 500 hull points of shipping at any one time.
Europa:
Europa is unique among the Jovian settlements. It alone has liquid water under the Ice. This makes Europa a vital strategic planet for the Jovian state. While other planetoids have water in the system, Europa is the most readily available source for water export.
Europa is connected to the rest of the solar system with a geostationary station with a 'space elevator' that connects Europa Station to the city of Atlantis (formerly known as Europa Prime). Atlantis is then connected via underwater mag-levs to Knossos, Thera, Troy, New Athens and New Marseilles.
Most Europans are still 'gen-mod normal' but more and more are being born with amphibian and rad-resistant mods so that they can experience their native habitat on a more personal level.
The city of Atlantis is renown for Atlantic Polytechnical Institute (API), widely considered a modern day MIT. It is important to note that API also has facilities on the Moon, in orbit around Jupiter and Earth, and a high energy research institution on Pluto.
The dominant languages of Europa are French and AmEnglish.
Jupiter L4 Trojans
The L4's lead Jupiter by several million miles along Jupiters orbit. They are a collection of rocks that have been settled by Belters and Corporate interests (primarily Vilslev Mining Inc.). This loose association of 25,000 or so exist my mining the Trojans for rare minerals and then using a linear accelerator to launch the refined material to a collection point in Jupiter polar orbit. The L4's have several asteroid settlements, the Vilslsev corporate station and hoards of familial 'clans' that rove the cluster in search of minerals and water.
Most importantly, the L4's supply Jupiter with heavy metals in exchange for water and Hydrogen. All in all this is a system that works very well.
Jupiter L5 Trojans
The people who live Jupiters L5 cluster are very similar to the people in the L4, and they trade with Jupiter more than any other Region for the same reason: it is cheaper. McMillan Industries and various Belter clans dominate the L5's.
Io
Io Industries is primarily responsible for the settlement and development of Io. Io is essentially a giant strip mining and energy production facility. About 8,000 people live on Io, running the nano-assembler and robo-mining facilities. There are another 5,000 employees in Io Station.
Ganymede and Callisto:
These moons hold various mining interests and various 'independent' settlements that do not fall under specific Regional authority but are considered part of the Jovian System.