The Miramichi fire
In case you thought that the "big" fires are all
out West, look up this one on the Internet! The Miramichi fire of 1825
in New Brunswick burned about 3,000,000 acres.
The only other fire that is similar in
size is the "Big Fire" in Idaho and Montana in 1910 (the one
in which "Big Ed" Pulaski was a hero). Both of these
fires were in the days before airplanes, let alone GPSs and the like,
so the actual sizes were approximate. But the fire went over the line
into Maine, and burned 800,000 acres in Piscataquis County alone.
Here's a map of the fire in New Brunswick:
(This map came off the Internet. I hope it's all right with its
source or that the source will let me know. He or she may well be
dead, of course. I don't know whether it was made about the time of
the fire, or more recently.)