The best place to have a port is in a location where the water is deep
enough and the ships will be protected from bad weather and big waves.
Ports also need easy access to roads and railways to transport cargo to and
from the ships. Many coastal cities have grown around good locations
for ports.
In the past, ports were built at the mouths of rivers. This gave ships
shelter and access to fresh water. The rivers were also used to
transport freight by barge to and from inland towns.