[fidelis]

Assuming that the Ark was originally interred on Mt. Nebo, it seems likely to have been retrieved after the Babylonia exile and eventually secreted elsewhere, almost certainly in or near Jerusalem. After all, one effect of the Babylonian exile was to unsettle Jewish religious practice and governance. In such a chaotic environment, the faction controlling the Ark might well have kept it hidden lest it be taken or misused by a rival faction or by the Romans after they arrived.

Of course those and other scenarios are possible, but I don't know of any documentary or other evidence for them. According the account given in 2 Maccabees (which states that the account there was taken from other records, probably now lost to us), Jeremiah, when he hid the Ark and the other Temple implements in the cave on Mt. Nebo, set very specific conditions for when they would be found again.

[Rockingham]

Can we be confident in that account, and that the ark was not recovered after it was hidden? Given the passage of time and the unsettled nature of that era, I think that other possibilities should be considered.