Here are Locations mentioned within the game, that are not specifically linked to the location of Aterra however could be nearby or from another island.
The location of God's Gift hometown. This information is only available in one of Ellie's bond events. Not much is known of the village apart from that Num-num nuts originated from the location, which are known to have a sweet distinctive taste. God's Gift lived in this location until at some point, left because of his families death and moved to Aterra, to seek out revenge for what happened.
(To follow through this information, involving where God's Gift lived, follow the video link and skip to around 20 minutes through. Apologies that it can't automatically skip to this part)
Shelgard; Ellie Troit's hometown when she moved from Gazel Village orphanage. She moved to Shelgard due to her close experience of death and was made to move there to get support from the church. Shelgard is closely located to Gazel Village, although it's distance to it is unknown. Shelgard consists of six cities, according to Ellie. Each city has a Cardinal presiding over one of the six elements and governing that city.
Notice that this location isn't mentioned within this game. However, was located to the original game. It's unknown if Granvania is one of the continent's, either near Aterra or a part of Aterra. However, it's unlikely to be a part of one large city or town, seeing as alike to Aterra-it had various places within it's location to visit.