Of unsuspended Suns —
Adds poignancy to Winter —
The shivering Fancy turns
To a fictitious Country
To palliate a Cold —
Not obviated of Degree —
Nor eased — of Latitude —
(F551) 1863 J562
Ah, that "fictitious Country" where the sun is always out in his warm, golden glory – how particularly glorious it seems when we are in the throes of winter. Dickinson says it adds "poignancy" to the winter, a sort of bitter pleasure in the conjecture of warmth without the actual heat. She repeats this idea, contained in the first three lines, in the following three: the "shivering Fancy" imagines a warmer place in order to lessen the cold.
So far, so good. The first two lines are so charming that I, at least, wouldn't demand much more of the poem. The alliterative hard 'c's of the first line contrast very nicely with the 's's of the second. Then we have the "poignancy" of winter, a "shivering Fancy" and a "fictitious Country" – each a rich and delightful image. The shivering fancy is surely imagination clothed as an ethereal wanderer searching for heat. The fictitious country reminds me of Hamlet who was imagining death as "The undiscovered country from whose bourn / No traveller returns."
Perhaps Dickinson was thinking of it, too. In a Dickinsonian twist, the last two lines describe a Cold that is not going to be stopped or lessened by degrees of latitude or longitude. A trip to Tahiti will not warm this marrow-deep, soul-deep cold. The land of "unsuspended Suns" may well refer to some Bible-class version of Paradise where heavenly rays are always shining on the saints and angels. If so, the poet lets us know by the word 'fictitious' that she is indulging in wishful thinking.
The last lines might also mean that the paradisical fictional warm country would be outside the effects of earthly geography. That would put us back in heaven but without having the narrator suffering from some existential Cold. I don't favor this reading, however, because it just doesn't fit as well to have the country obviated and eased as it does the Cold.