where did the phrase red light district come from

The exact origin of the phrase “red light district” is a bit murky, but there are two main contenders:

Red Lanterns: This theory suggests the term comes from brothels using red lanterns to discreetly signal their services. Railroad workers, who frequented these establishments, might leave their own red lanterns outside as a signal they were there. The collective glow of these lanterns supposedly gave the area its name.

American Wild West: Another theory claims the term originated in areas like Dodge City, Kansas, which had notorious red-light districts during the 19th century. Here, “red-light” might have simply referred to the area’s reputation for prostitution.

While the red lantern story is popular, the earliest documented uses of “red light district” seem to be from the late 1800s in the US, lending some weight to the Wild West theory.