In D&C 75 the Lord calls the Elders of the Church to serve in "eastern countries" which we now understand refers to the Eastern States of the USA. Why do you think the Lord would refer to these States as 'eastern countries'?
It could be that each individual state really saw itself as a 'country' in effect they are with specific laws governing their territory and it is merely the union of agreement to form a Federal State that made them all the USA as it is today.