So I came across this interesting article yesterday, listing the gravesites of all of the presidents of the United States (apart from those who are still alive). It is illustrated by this lovely map:

The westernmost tomb is that of Ronald Reagan in California; the southernmost is Lyndon B Johnson in Texas; the northernmost is Calvin Coolidge in Vermont. But who is easternmost? Both John Adams and John Quincy Adams rest in the crypt of the United First Parish Church in Quincy, Massachusetts. It must be one of them.

This charming news piece has CBS reporter Levan Reid exploring the crypt and inspecting the dead presidents for himself. As seen from the entrance to the burial chamber, John Adams is on the left, followed by his wife Abigail, their son John Quincy, and finally John Quincy Adams’ wife Louisa (the only First Lady born outside the United States, apart from Melania Trump).

It’s not completely clear from this film which way round they are with respect to the rest of the church. But Openstreetmaps suggests that the crypt is at the eastern end of the church, with John Adams’s tomb the northernmost of the four and a little to the west, and John Quincy Adams therefore the easternmost of the dead presidents.

But next time I am in that part of the world, I think I will go have a look for myself.

Edited to add, 28 August 2022: I was wrong, as I discovered when I visited Quincy today. In fact the crypt is located below the portico at the western end of the church, accessed by a staircase from the interior. John Quincy Adams and Louisa are in the northern end, slightly west of John and Abigail. John Adams père is therefore the easternmost of the dead presidents.