Geologists say the 4.5 magnitude aftershock occurred just before 12:40 a.m. local time and was centered about 5 miles (8 km) northwest of Mount Carmel.
That was the same epicenter where the initial jolt brought down a chimney and caused light damage around that small town before dawn on April 18.
The shaking was also powerful enough to knock bricks off older buildings as far away as Louisville, Ky., and to be felt as far away as Atlanta, nearly 400 miles (640 km) from the epicenter.
The Monday morning aftershock was the 18th since Friday and the second strongest, according to the U.S. Geological Survey.
The strongest registered a magnitude of 4.6 about 5 1/2 hours after the original quake.
WFIE television reports a farmer near the Illinois epicenter says one of his chickens laid a very unusual egg around the time one aftershock jolted the area.
Butch Shirley told the station that on the same morning of a 4.1 aftershock, one of his chickens laid an egg that was twice the normal size, was multi-colored and had odd-looking ridges. No such eggs had ever been seen before on his farm, and Shirley is convinced the mutation was due to the shaking.
