If you mean a neighborhood, no. SimCity4 is for making new neighborhoods of your own design. There will be neighborhoods which ship with the game if you are not interested in doing the terraforming and roadlaying with SC4. So, you don't need to have SC4 to be able to have your Sim's neighborhood.
If you want custom terrains, yes you will need SimCity 4. However you can always download the custom terrains off sims fansites and use them in your game. No you will not need SimCity 4 to build custom neighborhoods.
