Inner Sphere

The Inner Sphere is an astrographical and political region of space, and an administrative sector of the Central Galactic Union, with historical precedent as a province of the Terran Empire. It is defined as an area of space within a 500 light-year radius around the Sol System. It is a region of great importance to human history; it contains the Sol System and Earth, the cradle of humanity, as well as many of the first human colonies. It is a densely-populated region of space with a high level of development and standards of living. The economies of its constituent worlds are largely characterized by technology, commerce, and the public sector, as well as light industry. The capital world of the Union is located within the Inner Sphere, as are many important military, business, and government centers.
Its existence as a cultural and sociopolitical region was long-established, but it was incorporated as a unified administrative province only in 2555 via an Organic Act, as were most other provinces during the Imperial Reform.
It is a densely-populated and -colonized region of space. While only comprising roughly 524,000,000 cubic lightyears of space, it possesses 544 Member Worlds, 1,600 Federal Colonies, and 6 Federal Territories. These worlds are home to around 2 trillion humans and androids (about 3.2% for the organic citizen population). They also house 1 trillion installed synthetic citizens, many of whom are employed in government or military service.