Students must participate in the regional science expo that covers where they attend school. Fairs in the system may determine their region by school, school district or may serve an area covering many counties. The at-large regional fair exists for those areas of the state not covered by any other regional fair. For example, a student who lives within the boundaries of the Beaverton School District but attends Jesuit High School will participate in the at-large regional fair.

All high school students must qualify at a regional science expo in order to attend the Intel Northwest Science Expo. Traditionally the top third of high school projects from a regional fair will move on to Intel NWSE. Each regional fair may also qualify a project or projects to attend Intel ISEF directly. High school students who are not in the defined area of any other regional science expo must attend the at-large regional fair. If you would like to petition to attend a fair outside your region you must contact Stephanie Jones at nwse [at] pdx [dot] edu by February 8, 2018. Students who participate in a fair outside their region are not eligible to qualify for Intel ISEF at the regional level.

CWOSE has a middle school division. Middle School students are encouraged to attend a regional fair if middle school projects are accepted, but may come directly to the state fair. The state fair enforces a 10 project limit per organization/school for the middle school division.

Aardvark Science Expo: Serves students enrolled in Oregon Episcopal School. Held in Portland.

Beaverton - Hillsboro Science Expo: Serves high school students enrolled in the Beaverton and Hillsboro school districts. Held in Hillsboro.

Central Western Oregon Science Expo: Serves Yamhill, Marion, Linn, Benton, Tillamook, Polk, Lane, Lincoln, Douglas, Coos, Curry, Josephine, and Jackson Counties. Held in Eugene.

CREST-Jane Goodall Science Symposium: Serves high school students enrolled in the West Linn - Wilsonville school district. Held in Wilsonville.

Gresham-Barlow Science Expo (At-Large): Serves high school students not covered by other regional fairs. Held in Gresham.

Portland Public Schools Science Expo: Serves high school students enrolled in the Portland Public Schools. Held in Portland.

COCC Regional Science Expo: Serves high school students in Deschutes, Crook, Jefferson, Wheeler, Grant, Wasco, Sherman, Gilliam, Morrow, Umatilla, Union, Wallowa, Baker, Malheur, Harney, Lake and Klamath counties. Held in Bend.