Mars was the first planet to see massive terraforming efforts in the late twenty-first century. While Mars is a big place, most people on the planet are concentrated in the cities built into the Labyrinth. The steep canyons provided the early colonies with shelter from the harsh storms caused by the initial terraforming efforts. The Martian colonies are divided by nationality. The Chinese have by far the largest and oldest presence on the Red Planet. Due to the Interplanetary Land Swap performed in 2115, the second-largest presence in terms of footprint is the Chelyabinsk Rus. The third presence are the United Cities of the Arctic Circle in their role as successor to the United States of America.

The true rulers of Mars are however corporations, first among them Hexacorp. The Red Planet attracted corporate governments who set up massive mining and factory operations there. Both state and corporate governments made sure that large numbers of workers were shipped to Mars as a cheap labor force. This labor force has in the centuries since grown to a thriving, if embattled, assortment of colonies.

The biggest Martian settlement, Tharsis City, is located inside the Noctis Labyrinthus canyon system in the western reach of the Valles Marineris valley. The vertical city sprawls throughout the western part of the labyrinth, where it is relatively safe from the Martian storms' wrath. Most of the Martian mining projects are either located in the relative vicinity of Tharsis, or are connected to the city by hardened monorail.

Most of Mars’ interplanetary travel is handled through a cluster of spaceports surrounding Olympus Mons, the tallest mountain in the solar system. Olympus is ringed with linear mass accelerators of many different sizes.

While different nationalities claim to represent different parts of Mars, the planet is governed by a unified body, the Mars Board. The powers present on the Red Planet realized it would be beneficial for all if instead of disparate colonies, all human efforts on Mars were centralized and run through one representative government. The Mars Board seats representatives from all nation-states as well as from corporate entities with substantial interests and investments in the Red Planet.

Most of the resources extracted from Mars do not stay there, but were shipped to the Venusian orbit, to construct the Seramis colonies, and also to Earth's moon to fuel the colonization there.

As a prospective colony world, Mars’ biggest disadvantage is the planet’s lack of gravity. Humans were not made for Martian gravity. Another is the lack of Earth’s magnetic field and the resulting much higher ambient radiation. Gene therapies helped some with those issues, but even today those artificial genes have by far not permeated the majority of the Martian population, and the average life expectancy of Martians is rather low compared to that of Earthling humans.

Similar to the situation on Luna, gravity serves as a tool of social discipline on Mars. Most Martian workers have no access to expensive gene therapies. Instead they rely on a steady supply of medical nanomachines that constantly fix the damages wrought upon their bodies by lack of gravity and radiation exposure. While this problem is not quite as severe on Mars as it is on the Moon, Martian workers still require frequent, bi-annually injections to arrest the effects of living in a gravity well that is weaker than Earth’s.

The success of the Seramis colony on Venus proved another nail in the coffin of the Martian colonies. The initial plan was to have Mars be an extractive productive colony world first, working towards a fully terraformed planet, welcoming more affluent citizens after the completion of the terraforming project. But transforming the Martian landscape and atmosphere was more expensive than the initial projections predicted, and the labor force turned out more unruly and less prone to willingly indulge absentee rule than Earth's corporate masters thought. With the Martian terraforming project stalled, the Red Planet's atmosphere is thrown in a violent turmoil, plagued by frequent, violent dust storms, rivaling those of the Terran stormlands in intensity, if not frequency.