Blake's poem is that, other than the line "In England's Green and Pleasant Land", there is no clue as to the location of Jerusalem. Fortunately everyone knows that Yorkshire is God's own county, even Wikipedia gets it right (and no I didn't just edit the page), which allows us to narrow down our search slightly. Unfortunately, Yorkshire is still an awfully big place; if it was a country it would have been higher in the medals table at last years Olympics than Australia! Fortunately this recently taken photo helps us place it more accurately.
Given that we have two wagons, one from Sheffield and one from Pensitone, I think Jerusalem must be somewhere in my local area!