That is, if the primary port loses communication, the secondary port quickly takes over.

Edgartown is well known as having been one of the primary ports for the whaling industry during the 1800s.

The primary ports for which it is responsible include:

Union troops briefly occupied the state's primary port, Galveston.

The city is southern Sulawesi's primary port, with regular domestic and international shipping connections.

The island quickly became Texas' primary port and a destination for immigration.

Houston quickly grew once the Channel was completed, and rapidly became the primary port in Texas.

Manzanillo is the state's primary port and tourist destination, located on the Pacific coast less than two hour's drive from the capital.

It serves as the primary port for the industrial area centered on the city of Hitachi.

It was the primary port of trade for the Arcot nawabs.