A Mars station as it is simulated in Lt. Paris' holodeck program on the USS Voyager.
The Martian Colonies are one of the oldest colonies of humankind and were established in 2103 on planet Mars. Among the pioneers who settled the first colony were some of Jean-Luc Picard's ancestors. (Star Trek: Generations; DS9: "In the Cards")
In 2105, Jack the Ripper, an entity feeding off pain and fear, killed eight women of the Martian colonies. (TOS: "Wolf in the Fold")
The Fundamental Declarations of the Martian colonies were an important step in the pursuit of individual rights. (TOS: "Court Martial")
The flag of the first of the Martian colonies was inspired by a velvet painting of a bullfighter. (DS9: "In the Cards")
In an alternate timeline, the Martian colonies were destroyed in a 2154 Xindi attack. (ENT: "Twilight")
Known citizens include Lieutenant Mira Romaine, a crewmember of the USS Enterprise who was born at Martian Colony 3 and Simon Tarses, crewmember of the USS Enterprise-D. (TOS: "The Lights of Zetar"; TNG: "The Drumhead)
Background
It seems very odd that Mars wouldn't be colonized until 2103, 40 years after warp drive was invented, and after deep-space expeditions like SS Valiant and Friendship 1 and after the Terra Nova colony established in another star system. The 2103 date may refer to the formal incorporation of the colonies as one body or the beginning of the terraforming project seen in ENT: "Terra Prime".