The Soufriere Hills Volcano Exclusion Zone covers the southern part of the island of Montserrat. The unpredictability of the Soufriere Hills Volcano has made 2/3 of the island a high risk place to go due to lava bombs (flying rocks), pyroclastic flows and lahars, and so the Montserrat authorities have excluded people from this area. Even so, some parts of the remaining 1/3 of the island are still vulnerable to these volcanic phenomena.
The area is split into multiple subzones with varying entry and use restrictions, based on volcanic activity. A hazard level system is used to determine the restrictions, with a risk level on a scale from 1 (no measured activity in more than 1 year) to 5 (present risk of severe volcanic activity like pyroclastic flows or dome collapse). As of writing, the current risk level is 2. This may be subject to change at any time due to volcanic activity, though.
Here is a list of the subzones, classified by their enterability at the current risk level:
Zones A and B: contains areas such as Salem, Old Towne, Olveston, and Belham. This area is open 24 hours, and most of it is inhabitable. Residences are occupied by local residents and visitors alike, and there is some commercial activity here. Under threat level 3 or lower, the area is open for 24-hour entry. But under threat levels 4 and 5, these zones may be subject to designation as daytime entry zones.
Zone C: contains areas such as Cork Hill, Richmond Hill, Weekes, Foxes Bay, and Delvins. This area is a daytime entry zone, meaning that it can only be entered during designated daytime hours. As such, much of this area is not currently occupied. The main exception is the geothermal site that is located in Zone C, where the potential of using heat to meet Montserrat's power needs is currently being assessed. Some of the buildings and infrastructure are in very poor condition. It is advisable to follow safety precautions before entering this area, such as listening for the emergency alarms or taking caution when crossing the Belham Valley. If the risk level drops to 1, the area may be opened for regular 24-hour occupation again.
Zone F: a zone further east that is dedicated to farming. Open for daytime entry.
Zone V: the main "exclusion zone" on the south end of the island. Includes the city of Plymouth, St. George's Hill, and the Soufrière Hills Volcano itself. This area is not currently open for entry by the public. It is not advisable to enter this area, and individuals entering it are subject to prosecution. There are various other hazards in the area as well, especially due to the lack of maintenance in destroyed areas. The volcanic hazard level system specifies that daytime entry to parts of Zone V may be allowed if the volcanic hazard level is 1; some individuals have reported visiting Zone V (and sometimes Plymouth itself) legally when accompanied by a guide. You can't see Plymouth by foot or car, but you can see it on boat tours offered locally, and from vantage points in Zone C and other areas on land.
Along roads, you will generally see a sign if you are about to enter a different hazard zone, or a "No Entry" sign if you are approaching the boundary to Zone V.