|| Arcadian Ocean
|| Small city
|| 2,053 merfolk, 1,890 aquatic elves, 742 locathahs, 277 cecaelias, 193 tritons, 179 siyokoys, 168 deep merfolk, 45 ceratioidi, 35 selkies, 26 ichthyocentaurs, 2 adaros, 32 other
Source: City in the Deep, pg(s). 65
Talasantri is an underwater city 250 feet below the surface of the Arcadian Ocean. Though populated by many aquatic races, it is dominated by merfolk and aquatic elves. The city is a sanctuary for many in a dangerous ocean, however, the residents are incredibly prejudiced against any surface-dwellers that visit.
Paizo published a major article about Talasantri in City in the Deep and used the city as the setting for that volume of the Ruins of Azlant (adventure path).