What about the story that's been assigned to both Australian aborigines and to Mayans/Incans? In both cases, the tale is that when the first European visitors showed up on the coast in great big ships, these were so outside the experience of the natives that they were ignored - too big to be experienced, and anyway on those first few sail-pasts, they did nothing of interest and vanished over the horizon again.
I'm thinking, Australia: great big outback, lots of deserts, active rivers are few and far between. If you can ford a stream or walk over a dried-up gully - the idea may never have occurred.
Mexico/Central America, as was: jungles. Elsewhere, fertile land offering what you need. Inaccessible rivers or ones flowing so strongly with lots of teeth in, so the local humans might be deterred. If you want fish, set up traps or use nets. Less scope or opportunity, perhaps? Less driving need?