There are
1,636 mi
from Boise, ID to Dekalb, IL
That's the driving distance. It would take 1 day 3 hours to go from Boise, Idaho to Dekalb, Illinois.
The flight distance (direct flight from Boise, ID to Dekalb, IL) is 1,392.60 mi.
1,636 mi = 1.61 kms