The Ballot Brief
Ada County, Idaho

Ada County Assessor

2 candidates are tracked for Ada County Assessor on the November 3, 2026 ballot: Erik Olson and Rebecca W. Arnold. Candidate information follows official Ada County election filings; verify with the official election office linked below.

About this race

2 candidates are on the November 3, 2026 ballot for Ada County Assessor, per the Idaho Secretary of State's candidate filing portal.

What this office does

Property assessor. The assessor determines the taxable value of every parcel of real estate and, in many states, of business property, using state-set methods and market data. Those values, multiplied by rates set by other elected bodies, produce property tax bills. The assessor also administers exemptions such as homestead or senior exemptions.

This race. Every voter in Ada County votes on this seat.

Idaho › Ada County › Ada County Assessor

Erik Olson

Democratic

Top priorities
  • Expand digital service availability and reduce wait times at the assessor's office.
  • Maximize property tax exemptions available to homeowners, including wildlife habitat exemptions.

Per the campaign site.

Biography

Erik Olson spent five years as head financial officer for state agencies focused on energy policy and public charter school administration, per his campaign site. He also worked three budget cycles with Idaho's statewide budget agency, where he oversaw public school funding exceeding 3 billion dollars, per his campaign site. He holds a bachelor's degree in political science and philosophy from Idaho State University and a graduate degree in public administration and non profit administration from Boise State University, per his campaign site.

Rebecca W. Arnold

Republican

Biography

Rebecca W. Arnold is on the November 3, 2026 ballot for Ada County Assessor, per the Idaho Secretary of State's candidate filing portal. No campaign website was found as of September 20, 2026.

Next on your ballotAda County Clerk

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Voting info and more

Voting info and more
Questions about this race

Who is running for Ada County Assessor in 2026?

2 candidates are tracked for Ada County Assessor on the November 3, 2026 ballot: Erik Olson and Rebecca W. Arnold. Candidate information follows official Ada County election filings; verify with the official election office linked below.

When is the Ada County Assessor election in Idaho?

Election Day is Tuesday, November 3, 2026. Registration deadlines, early voting dates and mail ballot rules for Idaho are on the Idaho election hub at theballotbrief.com.

How do I see my exact Ada County ballot?

Enter your ZIP code in the lookup at theballotbrief.com for the statewide and congressional races, or a full street address to add the county, city and district contests for that location.

Verify this race

Candidate roster from official Ada County and state election office filings, last verified September 27, 2026. Bios and priorities carry their attribution inline.

Cross-check with the official Idaho election office, or see the full Ada County sample ballot and your exact ballot by address.

The rest of your Ada County ballot

39 tracked races in Ada County, Idaho. Landed here from another county's search? Look up your own ballot below.

Also on your ballot
Ada County Commissioner, District 1Ada County Commissioner, District 2Ada County CoronerSee all 39 Ada County races
Candidate profiles
Erik Olson, full profileRebecca W. Arnold, full profileOfficial Idaho election office