Find where inodes are being used

So I received a warning from our monitoring system on one of our boxes that the number of free inodes on a filesystem was getting low. df -i output shows this: Filesystem Inodes IUsed IFree IUse% Mounted on /dev/xvda1 524288 422613 101675 81% / As you can see, the root partition has 81% of its inodes used. I suspect they're all being used in a single directory. But how can I find where that is at?