These were troubled times. And Astor's men could not find a route across the Rockies. But while trying,t hey learned of difficulties with the Native Americans on the route they planned. So they made a wide detour south.
This detour was not planned. But by complete accident they stumbled through a wide low trough between the high Rockies peaks.
It was even suitable for wagons!
They were well south of their planned route, so they called this gap in the mountains the South Pass.
