Where the theory started
The Hammerfell theory isn't new speculation invented after the 2018 teaser. Fans had been asking for a return to Hammerfell for years before that trailer even existed, largely because it's one of the few Tamriel provinces that hasn't been the focus of a mainline game since Daggerfall in 1996 (the standalone spinoff Redguard visited it in 1998, but that's a different kind of game entirely). When the teaser dropped, it gave that existing wishlist something to actually point to.
What the 2018 teaser actually shows
The trailer's landscape shots, sweeping desert canyons, red rock formations, and coastal cliffs, read to a lot of viewers as a strong visual match for Hammerfell's established geography, which lore has always described as an arid, canyon-heavy region home to the Redguard people. It's genuinely suggestive. It is not, on its own, confirmation. Bethesda has never released a statement naming the province, and teaser trailers in this series have played with imagery loosely before.
Why High Rock usually gets mentioned too
Hammerfell shares a long, tangled political history with its northern neighbor High Rock, the Breton homeland, and the two provinces have been paired together before, most notably as the joint setting of Daggerfall. Because of that history, a lot of fan theories don't treat this as a Hammerfell-only bet, they expect Bethesda to build out both provinces together the way Daggerfall did, just at a much larger scale.
How seriously should you take this?
Treat it as the leading theory, not a confirmed fact. It's the setting most consistent with the available evidence and the one the community has rallied around hardest, but "most likely" and "confirmed" are different things, and Bethesda has stayed quiet on purpose. If you see a headline stating the setting as settled fact, that's the writer's opinion presented as news, not something that came from Bethesda.
Want to revisit Hammerfell's history before the next game?
Shop Elder Scrolls Games →Curious about the rest of what's known? Head back to everything we know about The Elder Scrolls VI, or read about what's actually confirmed on the release date.