Canadian National

They go all the way to the Gulf of Mexico.  See pic of map below.  The red route is the mainlines.  Also, the link shows the entire North American network.

http://cnebusiness.geomapguide.ca/

Well, a quick Google search found this CN System Map showing that they do have trackage in MS:  http://www.cn.ca/en/repository.../maps/cn-network-map  

The CN runs right through my home town in Lake Villa, Il., on the Wisconsin Central tracks to Chicago.  They run a clean ship.  A lot of cool color schemes, different locomotive types, and all are sparkling.  I see some original BC Rail motors and IC Central too.  Runs right next to the beach.  That's a mighty fine road by me.

they own the old Y&MV, GM&O, IC, ICG routes

Following CN's purchase of Illinois Central (IC) and a number of smaller US railways it also has extensive trackage in the central United States along the Mississippi River valley from the Great Lakes to the Gulf of Mexico.

Yup, they're everywhere - there are Illinois Central diesels and cars all over Canada too 

Here is a couple favorites

Once again the knowledge base of the forum is astounding.  That explains alot, as a kid I remember seeing GM&O and IC operating in that area.  Heck, I remember the good old days here in Northwest Florida when the L&N and Frisco were the two major roads.