Is Whidbey Island the longest in the contiguous United States? The truth is complicated.

Nature · Published 3 October 2026 Swipe more like this →

In short: Often cited as the longest island in the continental U.S., Whidbey Island holds a complex geographical status. Stretching 37 miles, it serves as a critical boundary for Puget Sound. Beyond its debated dimensions, the island is a tapestry of naval history, artistic communities, and a lost nuclear depth charge.

Located about 30 miles north of Seattle, Whidbey Island is the largest landmass in Washington state. Its geography is defined by its length, spanning roughly 37 miles from north to south, while its width fluctuates between 1.5 and 10 miles. While frequently labeled the longest island in the contiguous United States, this claim is contested by experts who suggest it does not hold that title. It remains the 40th largest island in the country, trailing behind major landmasses like Long Island and Padre Island.

The island's history is marked by both colonial exploration and indigenous heritage. Originally home to the Lower Skagit and Snohomish peoples, it was first sighted by Europeans in 1790 during a Spanish expedition. By 1792, Captain George Vancouver had fully explored and mapped the area, naming it after his master, Joseph Whidbey. The island later became a site of significant 19th-century settlement, notably through Colonel Isaac N. Ebey, who established the first permanent white homestead in 1850. His tenure was cut short in 1857 when he was killed in a retaliatory act by Haida visitors.

Today, the island is split into two distinct economic zones. The northern end is dominated by the Naval Air Station Whidbey Island, fostering a service-based economy centered on Oak Harbor. Conversely, the southern region leans into tourism, small-scale agriculture, and a vibrant arts scene. The island also contains unique historical oddities, including a lost Mark 90 nuclear depth charge that fell into Puget Sound in 1959, and Ebey's Landing National Historical Reserve, which was established in 1978 as the first of its kind in the nation to protect local rural culture.

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