As soon as you want your society become farmers, i recommend you any place with very fertile soil.

Chernozem is one of the high ferile soil,a nd quoting wikipedia:

There are two "Chernozem belts" in the world: from eastern Croatia (Slavonia), along the Danube (northern Serbia, northern Bulgaria (Danubian Plain), southern Romania (Wallachian Plain) and Moldova) to northeast Ukraine across the Black Earth Region and southern Russia into Siberia, and the other in the Canadian Prairies in Manitoba. Similar soil types occur in Texas and Hungary. Chernozem layer thickness may vary widely, from several inches up to 60 inches (1.5 metres) in Ukraine.

Which and places marked as red on map, might be best for that kind of society.

As soon as you want your society become farmers, i recommend you any place with very fertile soil.

Chernozem is one of the high ferile soil,a nd quoting wikipedia:

There are two "Chernozem belts" in the world: from eastern Croatia (Slavonia), along the Danube (northern Serbia, northern Bulgaria (Danubian Plain), southern Romania (Wallachian Plain) and Moldova) to northeast Ukraine across the Black Earth Region and southern Russia into Siberia, and the other in the Canadian Prairies in Manitoba. Similar soil types occur in Texas and Hungary. Chernozem layer thickness may vary widely, from several inches up to 60 inches (1.5 metres) in Ukraine.

Which and places marked as red on map, might be best for that kind of society.

EDIT

If it is full reboot, and we have similar circumstances when our civilization was created, i think it is worth to mention about places where sivilisation emerged in our world.

• Fertile Crescent : Egiptians and Sumerians
• Indus river : Harappans
• Yellow River : Ancient China (Xia Dynasty)
• Central Andes : Norte Chico
• Mesoamerica : Olmecs