You can delete territories anytime you want in Freshsales. When you delete territories, the existing records are still assigned to the territory, but new leads would not be assigned to it. 

To delete a territory, 

1. Login to Freshsales as an administrator.
   
2. Go to Admin settings > General settings > Territories.
   
3. From the territories list view, click the Delete icon beside the territory you want to delete.
   
4. A confirmation dialog box appears. Click Yes to delete the territory.