The American Territory of New Mexico was not created until 1850, three years after the year mentioned in the opening narration, and in the episode itself. In 1847, it would have been Spanish New Mexico.
Narrator: The year is 1847, the place is the territory of New Mexico, the people are a tiny handful of men and women with a dream. Eleven months ago, they started out from Ohio and headed west. Someone told them about a place called California, about a warm sun and a blue sky, about rich land and fresh air, and at this moment almost a year later they've seen nothing but cold, heat, exhaustion, hunger, and sickness. This man's name is Christian Horn. He has a dying eight year-old son and a heartsick wife, and he's the only one remaining who has even a fragment of the dream left. Mr. Chris Horn, who's going over the top of a rim to look for water and sustenance and in a moment will move into the Twilight Zone.
Christian: I may be crazy, or the world may be turned upside down but I know I've been put here for a reason. A reason.
Charlie: Short trip, Chris. Nothing much on the other side, was there?
Christian: You'd be surprised, Charlie. There's a whole lot on the other side of that rim. There'll be highways and many new things. A whole new land. You know what, Charlie? It was people like us, we made it happen.
Narrator: Mr. Christian Horn, one of the hardy breed of men who headed west during a time when there were no concrete highways or the solace of civilization. Mr. Christian Horn, family and party, heading west, after a brief detour through the Twilight Zone.