The Planet Datacenter Çap et

Our data centers are at The Planet. All of our servers (shared and dedicated) are located in Dallas, Texas or Houston, Texas.

I apologize, but you cannot choose which datacenter houses your server.

How can I tell which data center I am on?

Just do a tracert to the ip and you will see if it's DLLSTX2, DLLSTX4, DLLSTX5, DLLSTX6, etc.