Washington, Oregon, California, Alaska, and Hawaii are the only states that border the Pacific Ocean, and together they stretch from the tropical islands of Hawaii to the Arctic edges of Alaska.

All five sit along the Pacific 'Ring of Fire,' the zone of frequent earthquakes and active volcanoes that circles the Pacific basin. Washington and Oregon have the Cascade volcanoes, including Mount Rainier and Mount St. Helens; Hawaii's Mauna Loa and Kilauea are among the most active volcanoes on Earth; and California sits atop the San Andreas Fault.

California is the most populous US state by a wide margin, with roughly 39 million residents, while Alaska and Hawaii are the country's only two non-contiguous states, both admitted in the same year, 1959.

The coastline also carries some of the country's most iconic natural landmarks, from California and Oregon's old-growth redwood forests to Washington's rainy Olympic Peninsula.

This quiz tests capitals and abbreviations across a region defined as much by the ocean it borders as by the land itself.

Alaska is so vast that it spans four time zones and comes within about 55 miles of Russia at the narrowest point of the Bering Strait. Oregon is home to Crater Lake, the deepest lake in the country at over 1,900 feet, formed inside the collapsed caldera of an ancient volcano. Denali, in Alaska, is the tallest mountain in North America at over 20,300 feet — taller than any peak in the contiguous 48 states.

Hawaii is the only US state made up entirely of islands, and it's also the only state where a native language other than English holds official status alongside it. Washington's Olympic Peninsula, meanwhile, is one of the wettest places in the contiguous US, home to a temperate rainforest that gets well over 100 inches of rain a year.