Longest in its kind across the globe
Where five of seven meet the shore
Here the rights are set in stone
To cruise along the world's floorWhere am I?
Hint 1
The two first guesses, the Mariana Trench and the Andes, are far larger and also more well-known than this place.
Hint 2
Shells of wisdom, in a warm basin
Within which lies a land of freemason
Hint 3
This location is in the United States. The initial riddle refers to three key pieces of information: one cultural, one geographical, and one biological
Hint 4
The phrase "set in stone" is figurative to suggest a strong value/occurrence that would be difficult to change
Hint 5
Toward evening from the father's waters
With lonely monarchs and the mockers
Hint 6
Just about all the pieces have been solved or alluded to in the comments and answers
Hint 7
Line 2 refers to sea turtles, as identified by @user2597523
Hint 1: locations on a similar scale (and nearby the correct place) have been mentioned in comments and guesses
Hint 2: line 2 refers to Freemason Island, as identified by @user2597523 and @pandy legend
Hint 5: line one refers to west of the Mississippi, as identified @pandy legend
The "cultural" component has not been identified, but is given by lines 3 and 4