At the very highest level, the IPv6 address space is divided into six main parts, each having its own purpose and meaning.
::/3 – Special addresses types
2000::/3 – Allocated unicast addresses
4000::/2 – FE00::/9 – Reserved unicast addresses
FE80::/10 – Link-local unicast addresses
FEC0::/10 – Site-local unicast addresses
FF00::/8 – Multicast addresses
The site-local addresses can best be compared to the IPv4 local ranges 10.0.0.0/8, 172.16.0.0./12 and 192.168.0.0/16 ranges, although they are unique to some extent.