Washington State Route 240

State Route 240
Map of the Tri-Cities and Hanford areas with SR 240 highlighted in red
Route information
Auxiliary route of SR 24
Maintained by WSDOT
Length	41.31 mi[1] (66.48 km)
Existed	1964–present
Major junctions
West end	SR 24 near the Hanford Nuclear Reservation
Major intersections	SR 225 near West Richland SR 224 in Richland I-182 / US 12 in Richland
East end	US 395 in Kennewick
Location
Country	United States
State	Washington
Counties	Benton
Highway system
State highways in Washington Interstate US State Scenic Pre-1964 1964 renumbering Former
← SR 231 → SR 241

State Route 240 (SR 240) is a state highway in the U.S. state of Washington. It travels diagonally from northwest to southwest within Benton County, serving the Hanford Nuclear Reservation and the Tri-Cities region. The highway begins at a junction with SR 24 and travels around Richland on a limited-access bypass. From there, it briefly overlaps Interstate 182 (I-182) and continues southeast as a freeway along the Columbia River into Kennewick, terminating at an interchange with U.S. Route 395 (US 395). SR 240 is one of the busiest highways in the Tri-Cities region, with a daily average of 76,000 vehicles on a section crossing the Yakima River Delta.

The riverfront route between Richland and Kennewick was part of a 19th-century wagon road and the Inland Empire Highway, a state road established in 1913. It was incorporated into US 410 in 1926 and was part of US 12 from 1967 to 1986. The highway through the Hanford Nuclear Reservation was established as a state highway in the 1950s and opened on July 14, 1965, to connect Richland to the Vernita Bridge on SR 24.