|Location||East Beleriand, Thargelion|
|Description||Tributary of Gelion|
The Greater Gelion was one of the two rivers that flowed together to form the source of long Gelion, that flowed along the eastern borders of Beleriand. The Greater Gelion rose beneath Mount Rerir in the northern Blue Mountains, and flowed southwestwards to meet the Little Gelion. It formed the eastern boundary of the lands controlled by Maglor during most of the First Age.