Guard helps preserve the environment, too. Part of the branch's job is fisheries enforcement and making sure that vessels don't exceed their legal fishing limit to ensure that the ecosystem stays intact.
Outside of Alaska, the Coast Guard fills a multitude of other roles, including maritime law enforcement. Here, south of Puerto Rico, Coast Guard aircraft follow and identify two alleged smugglers.
The Coast Guard is also tasked with interdicting drugs that may be smuggled into the US along various waterways.
A Coast Guard Cutter Stratton boarding team investigates a self-propelled semisubmersible interdicted in international waters off the coast of Central America on July 19, 2015.
The Coast Guard also plays a key role in ensuring that the nation's most important ports are secure. Here, Coast Guard members demonstrate tactical small-boat operations in Honolulu Harbour.
In Puget Sound, the Coast Guard carries out frequent security operations to protect ferries that shuttle more than 22 million people in and out of Seattle each year.
And in New York Harbour, the Coast Guard ensures that shipping lanes stay open and protects against any potential acts of terrorism.
A boat crew from Coast Guard Station Port Canaveral, Florida, enforces a safety and security zone during a rocket launch off the coast of Cape Canaveral on June 24, 2016.
The Coast Guard operates internationally as well. In Shanghai, for instance, members of the US Coast Guard help train their Chinese counterparts.
Coast Guard ships can travel pretty far south as well. Here, the USCG Cutter Eagle anchors near the Galapagos Islands off the west coast of South America.
Select members of the Coast Guard are also trained to Snuba -- a method of diving similar to Scuba in which the diver breathes air from a tube connected to a ship. Here, a member of the Coast Guard Snubas for the first time off the coast of Honduras.
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