The world of Stonegate is placed in the future, a century or so after a collapse of Western civilization and a desperate struggle to rebuild. The story does not focus on the collapse, itself, but on a sort of Medieval society that emerged from the ashes of the old.
Rebuilding was complicated by the fact that much of our infrastructure is fragile and dependent of highly-skilled technicians to keep it all operating. If they became unable to function, the engines would soon stop, and be very difficult to restart.
A century after the collapse, the population is a small fraction of what it is today. Much modern technology has been lost, or remains only as rusted curios and third-hand memories. Even the English language has changed. Scholars, called lore-men, still read and speak English, but the speech has drifted toward a sort of creole English, very much simplified, called the Common Tongue.
Place names have drifted a bit. Some of the old names remain, but not all. Some of the changes have shortened the names, garbled them, or replaced them with another name entirely. Stonegate is an example of the latter.
Lore-men remember that Stonegate was once called Fort Collins, and that it had once hosted a university, a place of higher learning. The university tradition lives on in a famous lore-house which preserves much of the old knowledge and many books that survived the fires of the book-burning.
The origin of the name "Stonegate" is disputed. A popular legend, almost certainly false, holds that in the early days, mere years after the time of troubles, survivors started building the city walls, and used stone facing on the wooden gates of the city. Others say the name refers to the pass to the west, which provided a gate through the mountains, which came to be called the "Western Wall." But whatever the reason, the old name is largely forgotten.
One feature that makes Stonegate somewhat unusual is that the inhabitants were able to preserve some old artillery pieces and, equally important, preserved the practical knowledge of how to load, fire, and maintain them. These are called the "town guns" and enabled the people of Stonegate to remain secure against bands of lawless marauders that looted and destroyed so much in the early days after the disaster.