Fort Salta is a Marleyan fortification and airship research base in the southern mountainous region of the continental mainland. It served as a rallying point for the surviving remnants of the Marleyan military in the final hours of the Rumbling.
Story: Upon arriving in Odiha, Yelena confesses to Armin Arlelt and Levi Ackermann about a strategic meeting she held with Eren Jaeger. She details a plan to cripple Marley's military forces with a partial Rumbling in order to secure Paradis Island's safety for several decades to come. When Eren expresses his uncertainty of her plan to attack the port city of Karifa to crush the Global Allied Fleet before it is ready, Yelena voices her concern about Fort Salta's airship base being a potential threat.
Trivia: Unlike the majority of Marleyan location names which are based in Latin or Italian nomenclature, "Salta" simply appears to be "Atlas" spelled backwards. This is also applicable to the original katakana in which the characters for Atlas are reversed. This may refer to its location being, when vertically mirrored, analogous to the of northern .
Source: Fort Salta (Anime), available under CC BY-SA 3.0.