Closest Idaho City to Portland, Oregon: It's Ontario — But It's in Oregon

Trick question: Ontario is the closest city to Portland, Oregon (292 miles / 470 km east via I-84) — but Ontario is *in Oregon*, not Idaho. It's the Malheur County seat, on the Snake River border.

Actual Closest Idaho Cities

Fruitland: 305 mi / 491 km from Portland. Payette County. 5,000 pop. Fruit orchards, onion sheds.
Payette: 310 mi / 499 km. Payette County seat. 7,500 pop. Snake River, historic depot.
Weiser: 325 mi / 523 km. Washington County. 5,500 pop. National Oldtime Fiddlers' Contest.
Nampa: 370 mi / 595 km. Canyon County. 110K pop (3rd largest ID). Treasure Valley hub.
Boise: 430 mi / 692 km. State capital. 235K pop. 6+ hr drive.

Why the Confusion?

Ontario, OR and Fruitland/Payette, ID form a cross-border metro (~55K) — "Treasure Valley West." Same labor market, media, shopping. But state line matters: taxes, laws, licenses, voting.

Portland → Boise Direct

I-84 all the way: 430 mi, 6h 30m (no traffic). Scenic: Columbia Gorge, Blue Mountains, Baker City, Ontario/Fruitland border strip, then Boise Valley. Winter: chains/carry chains required OR/ID.

If you need Idaho, Fruitland is the gateway — 13 miles past Ontario.