Lochsea was a city near the souther-edge of the Agras Plain, along the Sword Coast. For a few centuries during the early part of the First Chaotic Period it had a thriving ship-building industry, based on lumber harvested up the length of the Agalu River.
Being only a stone's throw from the Seacrest Spire Flight, the humans at Lochsea were not tolerated for long, and the port city was soon destroyed. It was rebuilt, destroyed again, and rebuilt a third time, before the dragons discovered the support-structure forcing the humans to keep rebuilding the city.
Seacrest then set upon the whole length of the rover, annihilating every settlement they encountered along the way. By the 3450s B.G.A., the only humans remaining near the Agalu were on the Kepama Plains, where the dragons had a truce.
For a short period of around a century starting in B.G.A. 310 and ending sometime after 215, Lochsea and the settlements along the Agalu were re-established, to build warships for the various factions fighting over the Agras Plains. This resurgence happened during a period of hybernation by the flight, and the city was ultimately destroyed again by Seacrest Spire.
Eieber made a treaty with the dragon flight, stating that any human presence west of New Hope and within a thousand miles of the river would not be tolerated, and in exchange, Seacrest would provide one hundred dragon warriors to help Eieber's cause. In the event the dragons did not uphold their end, all land north of the Agalu River would be ceded to human control.
In A.Y. 1127, historians determined that only ninety-seven dragon warriors had aided in Eieber's campaign, thus making vast tracts of previously unavailable land ready for colonization. The dragons, eager to uphold their word, ate several historians, and the rest fell into line, stating unequivocally that one hundred warriors had fought.
In A.Y. 1616, delegates from High Mountain Flight (who had a long-standing land dispute with Seacrest) acted as a neutral third-party in arranging a new treaty between Seacrest and the Alliance. The High Mountain dragons argued that, since Seacrest flight's effective area of command did not extend as far as the Agalu, human settlement should be allowed in the area (the entire Agras was considered dragon territory, and by then had a population in the hundreds of millions).
In the end the dragons agreed, and timber trade along the Agalu resumed, with Lochsea acting as the gateway to the rest of the world.