Oregon's 15th Senate district

District 15 of the Oregon State Senate comprises central Washington County, including most of Hillsboro as well as Forest Grove and Cornelius. It is composed of Oregon House districts 29 and 30. It is currently represented by Democrat Janeen Sollman of Hillsboro.

Election results
District boundaries have changed over time. Therefore, senators before 2021 may not represent the same constituency as today. From 1993 until 2003, the district covered parts of the northern Willamette Valley; from 2003 until 2013, it stretched from Rockcreek west to Forest Grove; and from 2013 until 2023, it stretched slightly north to cover Helvetia.

The current district is very similar to its previous iterations, changing only by losing North Plains and parts of south Hillsboro and adding rural land south of Cornelius and Forest Grove.

The results are as follows: