au fin fond

deep in the depths of

→ au
phrase Rare #45,008
deep in the depths of Often used for a remote or very faraway place, similar to “in the middle of nowhere.” It is followed by de or du/d' plus a place or thing.
FR: Ils vivent au fin fond de la forêt.
EN: They live deep in the forest.

Elle n'était pas destinée à rester au fin fond des montagnes.

She wasn't meant to stay deep in the mountains.

— Le Conte de la princesse Kaguya (2013)

On a retrouvé ses restes au fin fond du Bengale.

His remains were found deep in Bengal.

— Porco Rosso (1992)

C'est bien au fin fond des montagnes du Nord?

Is it really deep in the mountains of the north?

— Le Château dans le ciel (1986)

Tu pourras repartir au fin fond des nuages.

You'll be able to return to the depths of the clouds.

— Les Invasions barbares (2003)