Incumbent State Senator Patty Kuderer, a Democrat appointed last year to fill the seat of now Lt. Governor Cyrus Habib, won over challenger Michelle Darnell, a Libertarian.
Early returns on Thursday show Kuderer with a sizeable lead ahead of Darnell 69% to 31%.
Kuderer is an attorney and a longtime community advocate. She was first appointed to the House of Representatives in September 2015 and won her re-election the following year. She was unanimously appointed by the King County Council to fill the vacant Senate seat.
Darnell, chair of the King County Libertarian Party, ran for District 48 of the state Senate in 2014, but was defeated in the general election by Habib. In 2016, Darnell ran for District 48 in the state House of Representatives but lost the race to Kuderer.
Legislative District 48 includes parts of Bellevue, Kirkland, Redmond and other areas of the Eastside.