Christopher Columbus did but it was named after Amerigo Vespucci
Magellan was the Spanish explorer who discovered South of Chile in 1529.
No South American explorer discovered Australia.To see who really discovered Australia, see the related question below.
The Mariana Islands were discovered by the Spanish explorer Ferdinand Magellan in 1521 during his circumnavigation voyage.
The Italian explorer Christopher Columbus discovered the US in 1492. Of course, it wasn't called the USA then. Also, there were already people living there.
Columbus
Spanish explorer Vasco Núñez de Balboa discovered the Pacific.
Henry Hudson discovered the Hudson Bay.
french explorer La Salle discovered the Ohio River around 1682, this explorer also explored the Mississippi River but did not discover it.
Abel Tasman was a dutch explorer that discovered New Zealand.
American Samoa was found before it became a US territory. It was simply the 'eastern' islands of Samoa. Samoa was first discovered in 1722 by a Dutch explorer named Jacob Roggeveen.Before becoming a U.S territory American Samoa was simply the eastern islands of Samoa. Samoa (as a whole) was discovered in 1722 by a Dutch explorer named Jacob Roggeveen.
Christopher Columbus accidentally discovered America for Spain.
Erik the Red.