We are planning a visit to the US we are staying in the Smokey Mountains for a few nights and then driving down to New Orleans. We are wondering if there is anything interesting to take in if we drive down via Chatanooga or can someone recommend a different route maybe taking in some of the Mississippi?

It's difficult to respond unless you tell us what you find interesting. Shopping? Historic sites? Restaurants? Natural wonders?

Chattanooga is a great small city - they've done a lot with the downtown and arts districts over the last 15-20 years. There's a fantastic aquarium downtown on the river and some fun shops in the North Chatt area. From there it's a pretty direct shot through Birmingham to New Orleans.

Thanks for your suggestion, can anyone tell me if the river area of downtown would take us very far off of the I24 on our way through?

The river area will take not you far off of 24. Chattanooga is a pretty small place (but surprisingly has lots to do).

You could head on down toward Montgomery for some interesting Civil Rights sightseeing and a great old city of the South.

All of the above are good suggestions, but if you've never seen the sugar sand beaches of the Florida panhandle I think you should head to the beach. A night at Pensacola Beach would be a wonderful addition to your trip. It will add about 2 hours to the drive, but IMO it would be very well worth it.