Easy one in the ' Riley Riddle [1]' tradition:
My prefix is unused.
My suffix is a forest removed.
My infix is a reunited analogue.
I am all alone but for a dog.
ACCEPTED]
He is in
New-found-land
My prefix is unused.
Unused is new.
My suffix is a forest removed.
A forest removed is just land.
My infix is a reunited analogue.
An analogue of being reunited is found.
I am all alone but for a dog.
[1] https://en.wikipedia.org/wiki/Newfoundland_and_LabradorNewfoundland is all alone because it is an island, but does have its Labrador [1] for company!
I guess Riley has been to...
Newark, or Newark-on-Trent [1], England.
My prefix is unused.
We called an unused thing as "a new thing".
My suffix is a forest removed.
The flood is coming, cut down all the woods to make an ark!
My infix is a reunited analogue.
Unite all the manpower to engage a war.
I am all alone but for a dog.
[1] https://en.wikipedia.org/wiki/Newark-on-TrentWell, there is one new built ark, so it is alone.
However, there is a place [2] that held a dog show [3] not far from the downtown area.