Port location is constrained by two physical characteristics of the site. The first involves land access, and the second concerns maritime access. Both must be jointly satisfied as they are crucial for port operations, which rely on a maritime / land interface. This interface takes the form of a buffer along the coastline (or a river depending on the port site) that experiences, due to an appropriate site, the accumulation of port infrastructures. The interface can also be subject to environmental and social conflicts. Thus, both land and maritime access can impair port operations and port development since a port benefiting from good land access but poor maritime access will be facing constraints and a port that has good maritime access but poor land access. However, maritime access is the attribute that can be mitigated the least. Activities such as dredging and the construction of port facilities are very expensive, underlining the enduring importance of a good port site. Such a site conveys the best marginal utility to port infrastructure investments.
Ports are a component of freight distribution as they support export and import activities. They are points of convergence (collection) of inland and coastal (shot sea) transportation systems, defining a port’s hinterland. This function may be direct, as freight reaches a port directly through road transportation, or indirect as freight reaches a port through an inland port or traffic consolidation at a feeder port and shipped by coastal transportation or short sea shipping. Likewise, ports are points of distribution to inland and coastal transportation systems. At the local level, every port provides services to ships with berths, docks, navigation channels, and repairs (occasionally), and services to merchandises with cranes, warehouses, and access to inland distribution systems.