🇺🇸 Keystone, United States

Keystone is a small city located in South Dakota, United States. It has a population of approximately 340 people. While it is not directly located on the coast, it is of interest to seafarers, shipowners, and crewing companies due to its proximity to the Missouri River, which provides access to inland waterways. The city does not have ports, shipyards, or factories producing ship parts.