Perimeter

Perimeter is Marathon's introductory zone and the first map most Runners will drop into on Tau Ceti IV. Set on the outer edges of the New Cascadia colony, the zone presents a sprawling open landscape of relay stations, collapsed infrastructure, and overgrown research outposts. It was originally established by the UESC as an expansion site when the Marathon expedition first made landfall, intended to help survey and understand the colony's outer boundaries. Today those ambitions lie abandoned, leaving behind a zone rich with corporate data caches, shady research findings, and the remnants of a terraforming project that never reached completion. The atmosphere is relatively open and forgiving compared to later zones, making Perimeter the natural starting point for Runners learning the fundamentals of extraction gameplay.

The map is divided by a glowing teal energy barrier called the Data Wall, which runs horizontally across the zone and defines the north-south split. Key points of interest include North Relay, a multi-floor relay station with elevated catwalks and a sniper perch on its antenna platform; Overflow, the most loot-dense structure on the map featuring a multi-floor complex with a locked storage room; and South Relay, a compound near the southern extraction point that offers a clean loot-and-exfil loop for squads who want to minimize exposure. The Station, situated on an eastern cliffside, contains an underground tunnel entrance and a key-locked vault holding high-tier loot, though it is heavily guarded. UESC patrols are present throughout Perimeter but in lower concentrations than on later maps, giving newer Runners room to learn enemy behaviors before facing more saturated combat zones.

Perimeter serves as the primary staging ground for faction contracts from all six major factions: CyberAcme, Traxus, MIDA, NuCaloric, Arachne, and Sekiguchi. Traxus tasks Runners with salvaging valuable corporate assets left behind during the UESC mission collapse, while CyberAcme's ONI system directs Runners to gather intelligence on the colony's fate. The zone's relatively accessible extraction points, including the stable North Extract, make it well-suited for Runners who want to prioritize consistent exfils over maximum loot value. For those willing to contest the Overflow building or crack the Station vault, the reward potential rises significantly. Perimeter is the best map in Marathon for building foundational knowledge of the game's extraction loop before progressing to the more demanding intermediate and endgame zones.