I'm looking for an upscale casual restaurant that will be serving the traditional thanksgiving dinner. If so, do you have to reserve a table.

You definitely need a reservation. You can use OpenTable

We have been Tersiguel's customers for 30 years....the family who owns the restaurant is truly French...they grow their own greens, vegetables, etc. Michel is the son of the founder and his wife Fernand and Odette. Charlie knows wine like no other....the food is beyond excellent! The service as well....yes please make a reservation.....

I don't know if they serve a traditional Thanksgiving dinner, but yes, you must make a reservation.