Arkansas

Green River County Detention Center
Episode: Folsom Prison Blues
A nurse that once worked at the prison has come back to haunt and kill some of the inmates. One of the prison guards is named Deacon, who is a friend of John Winchester.

Museum of Anthropology
Episode: Folsom Prison Blues
Dean and Sam break into the museum in order to get themselves into Green River County detention center.

California

Centennial Bridge, Jericho
Episode: Pilot
Sam and Dean investigate a number of mysterious deaths that all occured on the bridge in Jericho. The cause was a Woman in White, who orginally killed herself jumping off the bridge after the deaths of her children.

Sam's Apartment, Palo Alto
Episode: Pilot
Sam and Jessica lived in an apartment, presumably on campus, while at Stanford. He kept at least one photograph of his parents in the apartment, but presumably, this was lost when the Demon attacked and murdered Jessica.

Stanford University, Palo Alto
Episode: Pilot
Sam had been at Stanford University on a full scholarship for 4 years and gained a 174 on his LSAT. He hoped to stay at Stanford and start pre-law, until his father went missing and Jessica died. The University is in Santa Clara County and is adjacent to the city of Palo Alto.

Colorado

Blackwater Ridge, Lost Creek
Episode: Wendigo
Located at co-ordinates 35-111, Blackwater Ridge is a remote camping/hiking area in the middle of the woods. It is cut off by canyons and is surrounded by rough terrain, dense forest and abandoned mines. It was also the home to at least one Wendigo.

Connecticut

Pierpont Inn, Cornwall
Episode: Playthings
Owned by Susan Thompson, the Pierpont Inn was the site of several fatal accidents. Dean and Sam investigated and discovered that the spirit of Maggie Thompson was haunting the hotel to avoid Susan and her daughter from selling it and leaving.

Illinois

Roosevelt Asylum, Rockford
Episode: Asylum
The asylum is located within the town of Rockford. The locals believe it is haunted and teenagers are often dared by friends to spend the night there. Sanford Ellicott was the chief of staff at the asylum and was performing some very unorthadox experiments on the patients there. He believed that if he could get the patients to vent their rage, it could help cure them of it. His experiment backfired and the patients became more and more angry until one night in 1964 they eventually rioted. Some patients and staff were killed, including Sanford, whose body was found stuffed into a small cabinet by Dean and Sam. Even dead, Sanford's experiments continued somehow, causing Sam to lose control and vent his anger on Dean. The bones of Sanford were eventually salted and burned, finally allowing the remainder of the spirits to rest there in peace.

Kansas

Dean and Carmen's House, Lawrence
Episode: What Is and What Should Never Be
According to the post that Dean receives, his address is #53 Barker Ave. He shares the apartment with Carmen.

Guenther's Auto Repair, Lawrence
Episode: Home
Also in Lawrence, the auto repair is owned by Mike Guenther, although it was once co-owned by John Winchester, presumably under a different name. John asked Mike to buy his share in the business after Mary's death.

The Winchester Home, Lawrence
Episode: Pilot, Home, What Is and What Should Never Be, Origins #1
Located in the city of Lawrence, Douglas County, this is the house where the Winchesters were living when Mary was killed by the Demon. The focus point of the house appears to be the nursery where six-month old Sam was sleeping at the time and this is the room in which Mary died. Although the house was badly damaged in the fire, it was able to be rebuilt and eventually became the home of Jenny and her two children. However, when the Demon had entered the house, it caused the house to become a magnet for evil. A poltergeist began attacking Jenny and her children and wanted them dead. The spirit of Mary Winchester was also still residing in the house and managed to defeat the poltergeist by sacrificing herself when it began attacking Dean and Sam. Missouri believes the house to now be free of any paranormal activities, but she will continue to keep an eye on the house, just as she has done since the original fire. The house number is 1481, although in Dean's fantasy universe, the house number is 1841.

Mississippi

Lloyds Bar / Crossroad, Greenwood
Episode: Crossroad Blues
Any crossroads is a place where deals can be made with demons, but this specific one was just outside Lloyds bar. George Darrow summoned the demon at the crossroads to make his deal. What he didn't count on was the demon hanging around afterwards, making deals with other people.

Nebraska

Church of Roy LeGrange
Episode: Faith
Roy LeGrange considers himself to be a faith healer. Every Sunday at 11am and 2pm, he runs two services in which he performs miracles - healing those people who modern science have failed. One can only assume that as Dean was healed at 4:17 in the afternoon, that he and Sam attended the afternoon service and that it lasts for a few hours. The church itself is simply a large white tent in the middle of a field and there are often protestors outside who disagree with LeGrange's power. In truth, Roy LeGrange had no power at all - the healing was all done by a reaper who was being controlled by LeGrange's wife, Sue Ann.

Harvelle's Roadhouse
Episodes: Everybody Loves A Clown, Simon Said, No Exit, Hunted, All Hell Breaks Loose Part One, All Hell Breaks Loose Part Two, Origins #3
The Roadhouse once belonged to a hunter named William Harvelle, until his death. It was then run by his wife, Ellen and served as an unofficial meeting place and headquarters for hunters. Ellen's daughter, Jo, worked there until she decided to leave and become a hunter in her own right. There is at least one arcade-type shooting gallery game. Ash lived in a room in the Roadhouse. The location of the Roadhouse at this time is not confirmed. This is speculation based on two facts: when Dean and Sam are driving to the Roadhouse, the station ID on the radio clearly indicates that they are in Nebraska; and a family of tourists are seen coming into the Roadhouse wearing "Nebraska is for lovers" t-shirts.

The Roadhouse was destroyed by a fire which is thought to have been started by Supernatural means. Ash was presumed to be killed in the fire, although Ellen survived. She was out buying pretzels at the time.

Nevada

Highway 41
Episode: Roadkill
For 15 years, the ghosts of Molly McNamara and Jonah Greeley continued to haunt the same stretch of the highway. Each year, on the anniversary of their death, the two spirits re-enacted the events that led to their deaths.

New York

Bela's Apartment
Episode: Bad Day at Black Rock
Bela Talbot lives in a very expensive looking apartment in Queens, New York, which is presumably paid for by her work as a bounty hunter. She shares her apartment with a siamese cat. She has an intruder alarm and a security camera installed to watch the entrance and parking area of the apartment block. She also has stashes of weapons hidden.

John's Storage Locker
Episode: Bad Day at Black Rock
Under the false name of Edgar Cayce, John kept a storage locker in Black Rock, Buffalo. He kept a number of supernatural demon-related items there, as well as several keepsakes from when Sam and Dean were younger. There is a devil's trap painted on the floor and at least one booby trap to ensure the safety of the contents.

Ohio

Crawford Hall, Springfield University, Springfield
Episode: Tall Tales
Crawford Hall was the location of several strange events over a relatively short period of time, including a suicidal professor, an alien abduction and an alligator in the sewer. However, all these occurances were caused by a Trickster who lived on campus, disguised as a janitor. Dean, Sam and Bobby believed that they had killed the Trickster, but that was simply another trick from him. It is possible he is still living on campus.

Trotter's Bar, Elizabethville
Episode: Sin City
A bar owned by Trotter, this appears to be a central location within the town. One of the barmaids is called Casey - at least until she was possessed by a demon.

Oklahoma

Oasis Plains
Episode: Bugs
Oasis Plains was a new housing development being built on the remains of a sacred Indian site near the Atoka Valley. 200 years earlier, a band of native Indians lived on the land until the American cavalry came along to move them out. The Indians refused to move, so for six nights, the cavalry came back and killed men, women and children. As the chief of the village died, he cursed the land, swearing that no white man would ever tarnish his land again. Every year at the spring equinox, a plague of insects appears for six nights to rid the land of those people the Indians consider interlopers.

Oregon

River Grove
Episode: Croatoan
When Dean and Sam arrive in River Grove, they find it almost deserted, except for several inhabitants who have become zombie-like murderers. They find the word Croatoan scratched into a telephone pole - the same word that was left at the abandonded Roanoake Colony. They located the town from a vision of Sam's, clarifying that this was the correct River Grove due to the signs advertising Crater Lake that he saw.

Pennsylvania

Moyamensing Prison, Philadelphia
Episode: No Exit
Also known as the Philadelphia County Prison, Moyamensing was, at one time, the home of H.H. Holmes - America's first serial killer. The prison was first opened in 1835 and closed in 1964. It was demolished in 1968. It was located at 10 St. and Reed St. [See a map of the area from Yahoo Maps]

Rhode Island

Our Lady of the Angels Church, Providence
Episode: Houses of the Holy
Located in Providence, this Catholic church had two priests, Father Gregory and Father Reynolds. Father Gregory was shot and killed on the steps of the church for his car keys - Father Reynolds admits that the area is touch neighbourhood. There is a crypt beneath the church where Father Gregory is buried and his tombstone is covered with wormwood - a plant associated with the dead who are not at rest.

Texas

Hell House, Richardson
Episode: Hell House
Once lived in by Martin Murdoch, the house became abandoned. A couple of local teenagers decided to pretend the place was haunted, decorating the inside with "supernatural" signs and symbols and started spreading rumours of Mordechai Murdoch, a killer who used to live there. Unfortunately, one of the symbols they used was a Tibetan spirit sigil, which allowed the idea of Mordechai to become real. The house was eventually burned down by Dean and Sam.

Wisconsin

City Bank of Milwauke
Episode: Nightshifter
The bank was the location that Dean and Sam ended up in the middle of a hostage situation when chasing the shapeshifter.

Lake Manitoc
Episode: Dead In The Water
A small town built around a large lake, an accidental death of a child led to numerous deaths by drowning. Due to a leak in the damn, the lake was being drained, which caused the spirit to increase the number of deaths in order to get closer to the people it blamed for its death.

Wyoming

Devil's Gate
Episode: All Hell Breaks Loose Part Two
Located in the middle of an old cowboy cemetary, the crypt was protected to prevent it being opened accidently. However, with the use of Samuel Colt's special gun, the Yellow-Eyed Demon succeeded in causing the Devil's Gate to be opened, allowing hundreds of demons to escape from Hell. The cemetary was protected by a pentagram formed from iron train tracks surrounding the site.