Why aren't all Slayers active at the Hellmouth(s)?

Question

The Hellmouth is an area :

in which the barriers between dimensions was particularly weak, allowing the creation of portals between Earth and several hell dimensions. For these reasons, the Hellmouth attracted demons and other supernatural creatures, becoming a "hot spot" for supernatural activity.

The most famous one was located in Sunnydale, right below the high school attended by Buffy Summers. Another was humorously mentioned to be located in Cleveland. Aside from those two, no others are known to exist.

So, why do Slayers bother living anywhere else?

It seems that Buffy and Faith are the only Slayers to ever take up residence in the area. The other Slayers shown on the show are located in Jamaica, China and New York City. The show never mentions any other Slayers as having history with Sunnydale or Cleveland. If there's a limited number of points on Earth where all of the demons are going or coming from, wouldn't it make sense to live there? And seeing as how most of the Big Bads of Buffy need the Hellmouth for their world-ending plans, wouldn't it make sense to guard it? Did evil-doers just not use the Hellmouth for apocalypse-things before Buffy arrived?

Is there a canonical answer, even one given in novels or comics? Or is there any rational explanation?

And I would imagine that "they didn't know it existed" explains it. It seems like the Hellmouth's whereabouts is as old a knowledge as any other, and definitely written about in the dusty old books as anything else on the show. Especially as modern technology and travel/communications came about in the 20th century, knowledge of the Hellmouth's location would be made available to the active Slayer.

Answer 1

The Hellmouth is certainly a font of evil, from which spews all kinds of nasty things. It is even one of the biggest and/or most significant such fonts of evil. That said, it is NOT the only one, nor is it the only way demons/vampires/etc can enter the world.

At least one other Hellmouth is confirmed in the series itself (located in Cleveland, Ohio). In the episode where Cordelia wishes Buffy had never come to Sunnydale, Buffy instead lived in Cleveland and presumably fought evil there.

Giles later (in Buffy Season 8, the comic series) refers to the Cleveland Hellmouth as 'second rate', indicating that it is less powerful/dangerous than the Sunnydale one.

Consider also the Seal over the Hellmouth - there are many Hellmouths, and there is direct evidence of several mystical secret societies, each with their own goals. The Seal is evidence that at least one other organization is dedicated to preventing the Hellmouth(s) from spilling forth destruction.

There's no reason to think that there are only the two Hellmouths, so Slayers can do good near any of them.

Similarly, the normal enemy of the Slayer is the vampire. It's possible that vampires first entered the world through a Hellmouth, but that is irrelevant now: Vampires are HERE. They spread like an infection. Bite, slay, and rise: another demon walks the world in human skin. They are intelligent, tough, and evil. They can move around under their own power, meaning that a vampire can spread his infection (or infestation) far and wide.

If all the Slayers focused on one or two Hellmouths, the vampire populations across the world would be uncontrolled.

A final point to raise: the Watchers don't know what drives the Choosing of a new Slayer. They don't know what it is that decides which Potential will be next in line. But we do know that the Slayer power was born of demonic influence. It's certainly possible that, freed from a mortal shell, the power is drawn to Potentials near significant amounts of similar power.

A Potential living in Moose Ridge, Maine, which hasn't seen a demon in several decades would be very unlikely to be called, were that the case. A Potential living in a downtrodden part of L.A. where two rival gangs of vampires are preparing for an underworld war that will spill into the streets and leave them running red with blood? Much more likely to be called.

Answer 2

Yes, but...

Potential Slayers seem (from memory) to be born into random families, and as all the Slayers are teenage girls, where they live is a function of where the family is, not where the demons are...

I would imagine if there was any kind of predictability to the appearance of Potentials or any kind of hereditary line, then the Council of Watchers would have taken steps over the years to maneuver families into place so that if the Slayer was activated, she'd already be on the scene.

Answer 3

I Would assume that the Choosing selects the potential that will be the best Slayer for the time and fate guides them to where they will be needed most during their life. So Buffy was chosen for her character and fate guided her to the Sunnydale Hellmouth as the Powers That Be probably foresaw the 7 years of Big Bads that be active there too. Hence why the Shadow Men from "Get it done" referred to Buffy as the last guardian of the Hellmouth. Buffy is the response to these Big Bads calamities.