Astrography was the discipline focused on studying the positions and variations observed in both naturally occurring and artificially created phenomena within the galaxy. Put simply, it represented the scientific endeavor of charting interstellar space.
The galaxy was classified as an SBa type and spanned 120,000 light-years in diameter. The Astrographic Survey Institute bore much of the responsibility for mapping endeavors following the Galactic Civil War.
The approximate number of stars totaled 400 billion, with about half possessing planets with the potential to sustain life. Of these, 10% actually developed life, while only 1/1000 of those developed sentient life (roughly 20 million).
The galaxy was segmented into several regions, which are listed here in order of increasing distance from the galactic center. These regions were further broken down into various sectors, systems, and planets.
Located at the galaxy's very center, the Deep Core (also known as Core Systems) was a relatively small area that concealed peculiar worlds. Due to the intense gravitational forces exerted by the multitude of stars, local spacetime experienced significant warping, rendering hyperspace travel extremely challenging. It was believed that the region was inaccessible until Emperor Palpatine discovered several secure hyperlanes leading into it. The area persisted as an Imperial stronghold for nearly two decades after the Battle of Endor.
The Core Worlds, an ancient region bordering the outer reaches of the Deep Core, were among the most esteemed, advanced, renowned, and densely populated planets in the galaxy. These worlds represented the original areas of Human settlement. The Galactic Republic, and subsequently all galaxy-spanning governments, originated in the Core Worlds and expanded outwards across the galaxy. It is hypothesized that Humans originated from this region.
The Colonies was the designation for a galactic region situated between the Core Worlds and the Inner Rim. It was among the first areas beyond the Core to undergo colonization, and the worlds found there were generally heavily populated and industrialized.
During its period of dominance, the Galactic Empire exerted considerable force in controlling the Colonies, which led to the New Republic rapidly gaining support within the region.
The Inner Rim was a galactic region positioned between the Colonies and the Expansion Region. Initially, it was simply referred to as "The Rim," as it was expected to represent the farthest extent of the known galaxy for centuries. However, the Expanded Rim (later renamed the Expansion Region) was opened up within a century of the Inner Rim's establishment.
Under Palpatine's rule, the Galactic Empire maintained ruthless control over the Inner Rim. Rather than engaging in rebellion, many inhabitants opted to flee to the Outer Rim Territories.
Following the Battle of Endor, the Empire, despite its unpopularity, maintained control over the region for a surprisingly long time. Many later expressed resentment towards the New Republic's slow pace in liberating the area. Despite joining the New Republic, many worlds harbored open fears that the government lacked the strength to maintain power. These concerns were validated by Palpatine's return, when the Empire reclaimed the majority of the Inner Rim.
The Expansion Region represented an experiment involving corporate-controlled worlds, where powerful corporations exploited the planets for their raw materials, metals, and ores, generating substantial profits. The inhabitants faced oppression, while the corporations systematically depleted entire stellar systems of their resources. Eventually, civil unrest spread from one system to another. The Galactic Republic eventually assumed control of the system, driven by growing pressure from its inhabitants, by restricting or expelling corporate interests. The worlds of the Expansion Region persisted as producers of raw materials and ores, but most natural resources had been depleted by the Imperial Period.
The Mid Rim, characterized by fewer natural resources (and consequently a smaller population) compared to many neighboring regions, was a territory where residents had to work diligently for everything they possessed. Several planets developed impressive economies, and pirate raiders frequently sought refuge in the relatively unexplored areas distant from major trade routes.
The Outer Rim Territories represented the last extensively settled area before reaching Wild Space and the Unknown Regions. It was scattered with obscure worlds and rugged, primitive frontier planets. Due to its distance from the Core, the region served as a haven for numerous supporters of the Rebel Alliance. The Empire's Grand Moff Wilhuff Tarkin was assigned the challenging task of bringing the entire Outer Rim under control.
The Tingel Arm constituted an outer spiral arm of the galaxy, situated along the edge of the Outer Rim. It housed the Corporate Sector Authority, a political entity that enjoyed semi-independence from both the Galactic Republic and the Galactic Empire. Under the Galactic Empire, the sector expanded from a few hundred to thirty thousand systems.
Wild Space represented the frontier of galactic society, separating the known regions of the galaxy from the Unknown Regions. One of Palpatine's final actions involved opening up a significant portion of this region to more extensive exploration. Wild Space differed from the Unknown Regions in that some parts of Wild Space had been explored, albeit not thoroughly, whereas the Unknown Regions remained entirely shrouded in mystery.
The term "Unknown Regions" most often referred to the vast, unexplored area (which some believed to lie outside the plane of the galactic disk) situated between Bakura and the Imperial Remnant, largely dominated by the Chiss Ascendancy. The Unknown Regions encompassed only a few billion stars, in contrast to the galaxy's total of 400 billion. For reasons yet to be determined, there was a scarcity of reliable hyperspace routes through the region. The "Unknown Regions" designation included uncharted areas within dense nebulae, globular clusters, and the galactic halo.
Various established pathways, such as hyperlanes, traversed the sectors. These routes were explored and established by spacers known as hyperspace explorers (such as Gav Daragon and Aitro Koornacht). Astromech droids were tasked with guiding spaceships along these routes.