According to the U.S. Census Bureau, the county has a total area of 2,183 square miles (5,650 km²), of which 1,804 square miles (4,670 km²) is land and 379 square miles (980 km²) (17%) is water.

The county is split in three parts by its landforms:
Eastern Jefferson County along the Strait of Juan de Fuca, Admiralty Inlet, Puget Sound, and the Hood Canal
Central Jefferson County, which is uninhabited and lies in the Olympic Mountains within Olympic National Park and Olympic National Forest
Western Jefferson County, along the Pacific Ocean.

Because of the mountainous barrier, there is no road lying entirely within Jefferson County that connects the eastern and western parts.
The most direct land route between the two ends of the county involves a drive of approximately 100 miles (160 km) along U.S. Route 101 through neighbouring Clallam County.
The mountains also block the damp Chinook winds, which make the climate much wetter in the west than the so-called eastern "banana belt" in the rain shadow.
According to the U.S. Census Bureau, the county has a total area of 2,183 square miles (5,650 km²), of which 1,804 square miles (4,670 km²) is land and 379 square miles (980 km²) (17%) is water.
The county is split in three parts by its landforms:
Eastern Jefferson County along the Strait of Juan de Fuca, Admiralty Inlet, Puget Sound, and the Hood Canal
Central Jefferson County, which is uninhabited and lies in the Olympic Mountains within Olympic National Park and Olympic National Forest
Western Jefferson County, along the Pacific Ocean.
Because of the mountainous barrier, there is no road lying entirely within Jefferson County that connects the eastern and western parts. The most direct land route between the two ends of the county involves a drive of approximately 100 miles (160 km) along U.S. Route 101 through neighbouring Clallam County. The mountains also block the damp Chinook winds, which make the climate much wetter in the west than the so-called eastern "banana belt" in the rain shadow.
Jefferson County, Washington