Whidbey Island (historical spellings Whidby, Whitbey, or Whitby) is the largest of the islands composing Island County, Washington. (The other large island is Camano Island, east of Whidbey.) Whidbey is about 30 miles (48 km) north of Seattle, and lies between the Olympic Peninsula and the I-5 corridor of western Washington. The island forms the northern boundary of Puget Sound.
Whidbey Island is home to 58,211 residents (according to the 2000 census). An estimated 29,000 of Whidbey Island residents live in rural locations.
Whidbey Island is approximately 55 miles (89 km) long (from the extreme north to extreme south), and 1.5 to 12 miles (2.4 to 19.3 km) wide, with a total land area of 168.67 square miles (436.9 km2), making it the 40th largest island in the United States. It is ranked as the fourth longest and fourth largest island in the contiguous United States, behind Padre Island, Texas (the world's longest barrier island); Long Island; and Isle Royale, Michigan. In the state of Washington, it is the largest island, followed by Orcas Island.
Whidbey Island has four lakes that are part of its interior hydrology: Cranberry Lake (inside Deception Pass State Park), Deer Lake (inside Deer Lake Park), Goss Lake and Lone Lake (both near the town of Langley).
Whidbey Island lies partially in the rain shadow of the Olympic Mountain Range to the west, and has a variety of climate zones. This can be observed by rainfall amounts – wettest in the south with average rainfall of 36 inches (910 mm), driest is the central area around Coupeville with average rainfall of 20 to 22 inches (510 to 560 mm), and turning moister again farther north with average rainfall of 32 inches (810 mm). Microclimates abound, determined by proximity to water, elevation and prevailing winds.
The only bridge that reaches Whidbey Island is the Deception Pass Bridge, State Route 20, which connects the north end of Whidbey to the mainland via Fidalgo Island. Prior to the completion of the bridge in 1935, Whidbey Island was linked to Fidalgo Island by the Deception Pass Ferry, which ran from 1924 to 1935. Modern ferry service is available via State Route 20 on the Coupeville to Port Townsend ferry, and via State Route 525 on the Clinton to Mukilteo ferry service on the southern east coast.
Travel on the island involves use of an extensive county road system, or city infrastructure depending on location, all of which act as feeders to the two state highways State Route 525 and State Route 20.
Whidbey Island's State Routes 525/20 is the only nationally designated Scenic Byway on an island. It is appropriately named the "Whidbey Island Scenic Isle Way."
Public transportation is provided by Island Transit.
Two public airports provide service to Whidbey Island. Whidbey Air Park is located 2 miles (3.2 km) southwest of Langley with a 2,470 feet (750 m) long runway. Wes Lupien Airport is located 3 miles (4.8 km) southwest of Oak Harbor with a 3,265 ft (995 m) long runway. In addition, there are approximately half dozen private dirt strips on the island.
The United States Navy operates two airports on Whidbey Island. The largest is a two-runway airport located at Whidbey Island Naval Air Station north of Oak Harbor. In addition, the Navy also operates a flight training facility named Coupeville Outlying Landing Field (Coupeville OLF) located just southeast of Coupeville. The Navy named USS Whidbey Island (LSD-41) in honor of the island.