March 13 is indoor nationals, so you're not going to find anything then.
Florida State Relays and Alabama Relays are the biggest meets typically the weekend right after nationals. Last year also had (in the east) Wake Forest Invite, Clemson Classic and the Tar Heel Early Bird.
"A runner" asked:
does anyone know of any track meets happening the week of March 13-21? especially south of Illinois?
One reply suggested that Sea-Ray is about that time. This needs correction; Sea-Ray dates are 7-10 April 2003.
However, I've observed that in years past meets have been scheduled in March at Florida State University in Tallahassee. When I coached a U.S. Army team we went to an FSU meet; it was well run despite some heavy rainfall.