The Bay of Belfalas was a large bay situated where Gondor meets the Great Sea, carved out of Middle-earth at the end of the First Age when Beleriand was destroyed.

The NĂºmenorians started sailing into the Bay of Belfalas by SA800, and in SA2350 they built the Haven of Pelargir just up the Anduin from the Bay.

After the sinking of NĂºmenor, Isildur and Anarion sailed up the Anduin from the Bay in the year SA3319. There they found peoples that were loyal to Elendil and in SA3320, they founded the Kingdom of Gondor - which included the entire coastline of the Bay of Belfalas from the Cape of Andrast to the mouth of the River Harnen.
Encyclopedia entry originally written by PotbellyHairyfoot