Madripoor is a small island nation south of Singapore in the Indonesian archipelago. Conquered by freebooters centuries ago, its heritage of piracy evolved into the present laissez-faire government, permitting virtually any business transaction provided that the status quo is not threatened. Madripoor does not allow criminal extradition from within its borders, making it an exotic diplomatic haven for many international criminals, who help maintain the island's stability through a sophisticated system of corruption. Located near a major trade route, Madripoor's harbor and dock facilities are among the most extensive in the world; dependent upon imports for virtually everything, Madripoor is renowned for both its high-tech luxurious Hightown and its poverty-stricken Lowtown.

During the 1930s and early 1940s, Madripoor was a home base to the mutant adventurer Logan, later known as Wolverine, who also used the alias of Patch and acted as the island's protector alongside his mentor Seraph; the island has long been of interest to the ninja cult known as the Hand, and in 1941 Seraph and Logan worked with the super-soldier Captain America against an alliance between the Hand and the Nazi Party. In later decades, Logan occasionally frequented Madripoor's branch of the interdimensional firm Landau, Luckman & Lake, where he worked with his friend Chang.

In recent years, the psionic entity called the Shadow King, a.k.a. Amahl Farouk, possessed the body of the young mutant Karma to hold court in Madripoor, although Karma was eventually freed from his control by her teammates in the New Mutants. After Wolverine and his teammates in the X-Men faked their own deaths, Wolverine again frequented Madripoor, acting as co-owner of Lowtown's now defunct Princess Bar, formerly managed by Seraph, with a man known only as O'Donnell. Among his friends during this period were pilot Archie Corrigan, superhuman p.i. Jessica Drew, half-extradimensional Rose Wu, corrupt but honorable police chief Tai, and banker-turned-crimelord Tyger Tiger. Wolverine helped maintain an uneasy truce between the various factions on Madripoor until he was framed for the murders of several of his friends by crimelord Nguyen Ngoc Coy and Madripoor's ruler, Prince Baran; when their deception was revealed, Coy turned on Baran and killed him, only to himself be killed by Tyger Tiger.

Control of Madripoor was soon usurped by the criminal known as Viper, who cemented her power via marriage to Wolverine in repayment of a debt of honor he owed her; Wolverine and others assisted Viper in repelling an alliance of the Hand and the terrorist organization Hydra. Later, Madripoor became the site of an attempted invasion of Earth by the interdimensional warlord named Khan. Viper helped organize a resistance force against the invaders, who were ultimately repelled by the combined forces of the X-Men and the costumed superhuman champions known as the Avengers.