Dayglow

 Dayglow, originally known as San Diego in the Wasteland before 2162, is a town upon the remains of San Diego, near the site of the Glow and located in southern California. 

Background
The town is north and west of the Glow, which can be seen from its borders.

The exact intensity of bombing on San Diego remains a mystery. However, dialogue suggests that the city was hit by at least one nuclear weapon.

Before 2161, the town was populated by an unknown number of people, some of whom later became the Followers of the Apocalypse, including Nicole, the founder of the Followers and her parents. Butch Harris also seems to have lived here for a time before moving to the Boneyard, and later the Hub.

After the exodus, due to the spread of sickness, the town was completely abandoned.

After 2162, a number of ghouls are rumored to live there, as part of the Great Migration from the Necropolis - once the ghouls learned of West Tek, they were eager to see if they could scavenge technology from the abandoned facility. The town was renamed Dayglow and some ghouls formed partnerships with scavenging companies from New Adytum and the Hub, and have built quite a profitable business. At least one super mutant, a refugee from the Cathedral, was also rumored to be working with the ghouls and humans in Dayglow.

In 2189, Dayglow became one of the five founding states within the NCR. A speech by NCR President Tandi at Dayglow is represented on the NCR $100 bill.

Before 2161

 * Butch Harris
 * Nicole

Appearances
Dayglow doesn't appear in any of the Fallout games, but is vaguely mentioned in Fallout (only as "near the Glow"), Fallout 2, Fallout: New Vegas, add-on Honest Hearts and The Armageddon Rag, Vol. 4.

Behind the scenes

 * Its old name is revealed in the Fallout Official Survival Guide.
 * Dayglow is likely a play on Daygo, a slang term for its old name San Diego.