Multiple realities(covers information from several alternate timelines)
Madison was a city in the state of Wisconsin.
In an alternate timeline in which Nazi Germany had invaded the United States, as of 1944 Madison was controlled by American forces. (ENT: "Storm Front", "Storm Front, Part II")
In a hallucination experienced by Hoshi Sato in 2153, Sato was told that Cyrus Ramsey dematerialized after transporter tests in Madison in May of 2146. (ENT: "Vanishing Point")
Madison was named on a map of the United States (Die Vereinigten Staaten von Amerika). Its location was represented by an orange circle.