It's called Centralia, Pennsylvania, and while not what inspired the games it is the place that inspired the setting for the films and they share quite a few similarities.
Centralia is a near-ghost town in Columbia County, Pennsylvania. Its population has dwindled from over 1,000 residents in 1981 to 10 as of 2010, as a result of the Centralia mine fire burning beneath the town since 1962. All properties in the town were claimed under eminent domain by the Commonwealth of Pennsylvania in 1992 (and all buildings condemned), and Centralia's ZIP code revoked by the Postal Service. State and local officials reached an agreement with the remaining residents allowing them to live out their lives there, after which the rights of their properties will be taken.
Very few homes remain standing in Centralia. Most of the abandoned buildings have been demolished by the Columbia County Redevelopment Authority or reclaimed by nature. At a glance, the area now appears to be a field with many paved streets running through it. Some areas are being filled with new-growth forest.
The remaining church in the town, St. Mary's, holds weekly services on Sunday and has not yet been directly affected by the fire. The town's four cemeteries, including one on the hilltop that has smoke rising around and out of it, are maintained in good condition. It is estimated that the amount of coal located around and under Centralia will sustain the fire for at least 250 years.
Centralia has been used as a model for many different ghost towns and physical manifestations of Hell. Examples include Dean Koontz's Strange Highways and David Wellington's Vampire Zero, and, as stated, the film adaptation of Silent Hill.
Knoebels Amusement Resort, in nearby Elysburg, features The Black Diamond, a dark ride/roller coaster based on the theme of a haunted coal mine. Near the end of the ride, trains pass a swirling, fiery vortex. Although this resembles popular depictions of the gates of hell, a sign identifies the location as Centralia.
With such a history it wouldn't be surprising if their were some spirits lingering in the town still. It is a great site for a horror movie and isn't surprising it has been used as a inspiration multiple times. I would love to visit this place one day.
If your interested in finding out more about the history of the town, here is well done documentary you might enjoy.