Conversation so far:
Where are the grand islands?
Grand Island is a town located in Erie County, New York, United States.
Did the Seneca people live on the Grand Islands?
The Seneca used the island for hunting and fishing.
Who claimed the land of the Grand Islands before the Seneca?
Before the Seneca, the Neutral Nation of Native Americans, also known as the Attawandaron were living on the island.
What else does this section mention?
By decision and order dated June 21, 2002, the trial court held that the Seneca ceded the subject lands to Great Britain in the 1764 treaties of peace.
Was there another ruling regarding the Seneca Grand Islands since 2002?
The United States Court of Appeals for the Second Circuit affirmed the trial court's decision on September 9, 2004.

Question: Why do they claim this land?
Self-contained rewrite: Why do the Seneca claim the Grand Islands?