How to find and unmount unresponsive NFS mounts? I turned off a machine exporting one folder which was mounted on my Mac using NFS.

How can I find and unmount the mount point ?

df does not return; it is probably stuck on this mount point, and I can't find a way to enumerate NFS mount points.
The mount command on the command line should give a list of all mounts, along with the mount point and the used file system, so nfs mounts can be identified as such.