Motor City Metahumans
While they aren't a part of daily life in the city, a surprising number of superheroes have operated out of Detroit in comic books of recent years. There have been a number of minor characters in small press comics (for which very little information is available), but a number have made substantial names for themselves.
Detroiter John Stewart was originally a secondary character, selected by the Guardians of Oa to serve as a backup to Hal Jordan, the Silver Age Green Lantern. During the various upheavals of the Green Lantern Corps in the 1980s, Stewart took on the role full time when Hal Jordan resigned his post. Over the following years, he gained and lost a wife (fellow Corps member Katma Tui), played an important role in the Crisis on Infinite Earths, accidentally destroyed an alien world, lost his position as Green Lantern (and nearly lost his mind), returned as leader of the post-Corps Blackstar force, and became paralyzed defending another world. Hal Jordan healed his paralysis before giving his life to save the sun, and John Stewart has now taken over again as Earth's Green Lantern Interestingly enough, John Stewart is now the only Green Lantern appearing in the Cartoon Network's interpretation of the Justice League, a decision based largely on the writers' liking the character best out of the different comic book versions. The Green Lantern Corps Guide has a full write-up of John Stewart's history through the Crisis.
Detroit native Will Everett first emerged onto the public stage when, at the 1936 Berlin Olympics, he and his teammate Jesse Owens stuck it to Hitler by bringing home numerous gold medals. Returning home, though, he was unable to find work except as a janitor in a laboratory. After serving as an unwilling guinea pig in experiments by the Ultrahumanite, he gained the ability to absorb the characteristics of whatever material he touched. He eventually helped defeat the Ultrahumanite, and became a character in DC's classic retro-Golden Age series the All-Star Squadron, where he periodically served as the writers' window into racial issues, such as the race riots that arose in Detroit during World War II. In 1942 his powers were transformed by yet another accident, this time providing him with magnetic powers (though oddly enough his original powers were inherited by his children).
In the mid-1980s, the Justice League of America went through a very rough patch. An alien invasion (initially Martians, but a different crowd after the Crisis on Infinite Earths) resulted in the destruction of their orbital base, and the team broke up in the aftermath of the loss. In an attempt to keep the torch alive, Aquaman brought together a group of novice superheroes to form the JLA Detroit. The team included Steel, Vibe, Vixen, Gypsy, and a number of veteran heroes including the Martian Manhunter and Batman. The team's headquarters were in an underground bunker in Detroit proviced by WWII hero Commander Steel (a teammate of Amazing Man, interestingly enough), who offered it to the team in exchange for them accepting his grandson Steel into the JLA. Eventually the JLA were evicted by Commander Steel (who was eventually revealed as a supervillain), and moved to New York. As part of the Legends miniseries, and the late-eighties revival of the JLA franchise, the JLA was disbanded under presidential order, and almost all of the new members of the team were killed by second-string supervillain Professor Ivo. Michael Kooiman includes a reasonably complete history of the JLA Detroit, beginning in the section labelled "6 Years Ago".
Witch Doctor was originally Dr. Jovan Carrington, a respected psychiatrist and the son of an anthropologist. Plagued by nightmares of his childhood, when he accompanied his father on his research in Haiti, Carrington eventually discovered that the visions were his ancestors attempting to contact him. With their guidance, he travelled back to Haiti and became an initiate of Voodoo, and used his knowledge to protect the public from the forces of evil. While WitchDoctor is not himself a native of Detroit, he is the creation of Detroit comics artist Kenjji. They were profiled together in an 2002 article in the Metro Times; notably, this was one of the articles plagiarized by the New York Times' infamous Jayson Blair.
The Black Superhero Museum has brief descriptions of many other lesser-known Detroit superheroes.