Restricted airspaces for all types of aircraft (unmanned and manned) are typically categorised into three main areas:
Permanent Prohibited Areas- for one reason or another, aircraft have been banned from entering these areas.
Restricted Areas- protect sensitive locations such as prisons and nuclear facilities.
Danger Areas- areas of military airspace used for activities such as fighter pilot training and weapons systems testing. Special Use Airspace's usually take the form of Danger Areas.
These areas are marked on aviation 'Visual Flight Rules' (VFR) flight charts which can be purchased online or at your local flight school. There are also apps such as 'Sky Demon Light' and 'Drone Assist' who have this information within their mapping databases.