Huh, my canon Courier is from New Arroyo, helps explain that Vault 13 suit too. I don't think Cass was born in New Arroyo based off this dialogue when you ask her about her parents. Her mother wasn't from Arroyo rather she was from one of the tribes east of the Colorado.
- ↑ The Courier: "Your mother was a tribal?"
Rose of Sharon Cassidy: "You know, like one of the tribes from the East - we got 'em out West, too. NCR's herding 'em up, though, domesticating them. Mom was from East of the Colorado, though, not sure what tribe. Was before the time Caesar rounded them up, made them Legion. She walked a hell of a way until she crossed paths with my Dad and he convinced her to stop walking. And lucky for me, he was a horny old bastard."
(Rose of Sharon Cassidy's dialogue)
- ↑ The Courier: "Tell me about your Dad."
Rose of Sharon Cassidy: "Not much to tell. He ended up walking East one day when I was young and never came back. Not a family deserter like some, though. Mom died waiting for him, and she had me to raise. She was sick but she held off dying until I was old enough to be getting into trouble with boys. As for Dad, I figure he just got himself lost or dead. Happens... and I'm not all boo-hoo about it, so save your glass for someone who's crying."
The Courier: "Any idea why he went East?"
Rose of Sharon Cassidy: "Not a clue. When he left, I was too in my crib to understand why, and around the time Mom passed, I was too into my teens to listen. Got his name, got this pendant, and that's about it. Gift from my Dad, along with my name. Rose of Sharon Cassidy. Mom said he got the name out of some Old World book about dirt pilgrims. Name sure sounds sweet, though. Anyway, pendant's a little rose. Originally thought it was one of Mom's tribal necklaces, but no, came from Dad."
Cassidy talks about how he'd like to travel to the Midwest, it's plausible that after helping the Chosen One defeat the Enclave he decided to try his hand at travelling there instead of settling down again. Got with Cass's mother for a while but once again decided to go. It is possible however that Cass's mother walked all the way from east of the Colorado to New Arroyo. Vault City is part of NCR by the time Cass was born, Cassidy used to live there, it is further east than most parts of NCR at the time and Cass ends up retiring there if you convince her to leave the Mojave and head back west. So I'd place my bets on her being from Vault City.