I felt it in the Edwardsville area quite strongly. I happened to be awake - woke up about a half-hour before. My cat was outside; when I let him in, he was quite clingy and vocal, but when the quaking actually began, I think he was asleep somewhere.
At first I wasn't sure what it could be. I looked outside to see if we had high winds (it was quite breezy yesterday) and also wondered about the refineries out towards the Wood River area, but when the trembling continued I decided it was indeed an earthquake.
I'm not quite sure how long it lasted. Long enough for me to arise from my chair, walk to the other side of the house to look out the window, and then back into the room where a picture hanging on the wall was rapping against where the brick chimney goes through the house. I held my hand against that to still it.
The birds commenced to chirp loudly. I don't think this began before the quaking, but rather afterward; yet, it's possible that I simply didn't notice as my mind was otherwise occupied.
Now that it is daylight, I see no damage. Our rickety backyard fence is still intact and standing, and our railroad-tie garden beds which are at risk of collapsing are also still intact.
I reported the earthquake on the USGS site here
Did You Feel It?
It took a good half-hour before I could find anything on the local news channels and the Internet news. The USGS site notes the epicenter at 38.450°N, 87.890°W which is near Olney, Illinois. This link gives rather detailed information
M 5.2 - ILLINOIS
However, I've seen a conflicting report noting the epicenter at Bellmont.
It should be noted that there was another earthquake in this area in 1987 of 5.1 magnitude, where the most serious damage was reported in Olney, and before that, in 1968 there was a 5.3 in the general region.
This is the Illinois Basin Ozark Dome, and is NOT the New Madrid.
Hope this is interesting and helpful.