Prior to the construction of Interstate highways and expressways, the roads used by Greyhound and Trailways buses conveniently passed through various city neighborhoods and major suburbs. And bus stations existed in some of these areas.
In smaller communities, the bus stations actually were primarily other businesses, which also sold bus tickets and provided station services.
In more recent years, the only surviving neighborhood Greyhound stations are at CTA rapid transit stations. But the fact that these rapid transit lines often use expressway median strips, often means that the stations are near the expressways anyway. And that the buses must not travel very far out of the way, to serve these stations.
In the past, Chicago's "satellite" cities (Aurora, Elgin, Joliet, Waukegan) received Greyhound service. But today's Interstate highways are often a few miles away from the downtown areas. And apparently, Greyhound has decided that these stations were too far out of the way. So in recent years, Greyhound discontinued service to all of these satellite cities.
Northwest Indiana/Calumet Region