Seattle to Portland: Distance and Drive Time

By the Miles Between Cities Editorial Team  ·  Last updated: October 2026

The distance from Seattle, Washington to Portland, Oregon is 145 miles in a straight line and 181 miles by road, which takes about 3 hr 37 min to drive in free-flowing conditions. Those three numbers answer three different questions, and this page keeps them separate on purpose: the straight-line figure describes the geography between the two city centres, the driving figure describes the road network that connects them, and the time figure translates road miles into the hours a driver should actually budget. Mixing the three up is the most common reason a trip between Seattle and Portland gets under-planned, so each figure below carries its own label and its own method.

Seattle to Portland at a Glance

Seattle sits in the West Coast and Portland in the West Coast. Seattle is the more northerly of the two cities and Portland the more southerly, with 2.08 degrees of latitude between them, while Seattle stands 0.30 degrees of longitude east of Portland. Those coordinate gaps are what the straight-line calculation turns into miles, and they also shape the trip: a pair separated mostly by longitude is a sunrise-and-sunset trip across time zones, while a pair separated mostly by latitude is a climate trip, where the weather at the far end can feel quite different from the weather at the start even when the road miles are modest.

The Straight-Line Distance: 145 Miles

The straight-line distance between Seattle and Portland — sometimes called the as-the-crow-flies or great-circle distance — is 145 miles (233 kilometres). We calculate it with the haversine formula, which measures the shortest path over the curved surface of the Earth between two latitude-and-longitude points. The two points used here are the internal points published for each place in the U.S. Census Bureau Gazetteer files: 47.6193, -122.3515 for Seattle and 45.5370, -122.6500 for Portland. Using an official, published coordinate for each city matters, because a distance is only reproducible if both endpoints are fixed and named; anyone can repeat this calculation from the same Gazetteer points and arrive at the same 145 miles. The straight-line figure is the right number for understanding how far apart the cities really are, for comparing this pair with other pairs on an equal footing, and as the starting point for flight-distance thinking. It is not, on its own, a number you can drive.

The Driving Distance: 181 Miles

No routed measurement is published for this pair, so the driving figure on this page is an estimate, labelled as an estimate wherever it appears. It is built by multiplying the straight-line distance of 145 miles by a circuity factor of 1.25 — the documented allowance, explained on our methodology page, for the way real roads bend, detour around terrain and funnel through junctions instead of following a straight line. That gives an estimated driving distance of 181 miles (291 kilometres) and, at an assumed average of 50 miles per hour, an estimated drive time of 3 hr 37 min. Treat both numbers as planning ranges rather than exact answers: on a corridor where the highway runs unusually straight the real road distance can come in below the estimate, and in mountain or coastal country it can come in above it.

The gap between the two headline figures — 36 miles, or about 25 percent more road than straight line — is normal, and its size tells you something about the corridor. A small percentage usually means a direct highway happens to run close to the straight line between the cities; a large one usually means terrain, water, a sparse road network or a major detour through an intermediate hub is forcing the road away from the direct line. Neither figure is "wrong": they measure different things, and a careful planner uses the straight line to judge the geography and the road figure to judge the day.

How Long the Drive Takes

Budget about 3 hr 37 min of wheel-turning time for the 181-mile drive from Seattle to Portland, and then budget more than that for the trip as actually lived. Routing and estimation both assume a moving vehicle; neither includes fuel stops, meals, rest breaks, roadworks, rush-hour approaches to either city, or weather. On a drive of this length, most drivers add at least one proper stop every two to three hours, and a sensible door-to-door allowance is the driving figure plus roughly ten to twenty percent. If the total crosses eight or nine hours, splitting the journey across two days is usually safer and more pleasant than pressing through tired, and if it crosses a time-zone boundary the arrival clock will not match the departure clock in the way your body expects. Both cities observe Pacific Time, so the clock does not change on this trip: a departure at nine in the morning and an arrival counted in the same zone need no adjustment, which makes same-day planning between Seattle and Portland simpler than on a cross-zone run.

Travelling in the reverse direction, from Portland to Seattle, covers the same 145 straight-line miles and essentially the same road distance, with a compass heading of roughly north instead of south. Small differences can appear by direction — one-way systems in each city centre, junction layouts and which side of a divided highway a service area sits on — but for planning purposes the pair is symmetric: the same figures, the same allowance for stops, and the same advice to check live conditions on the day.

Frequently Asked Questions

How far is Seattle from Portland?

It is 145 miles in a straight line and 181 miles by road (estimated), as itemised in the comparison table above.

How long does it take to drive from Seattle to Portland?

About 3 hr 37 min of driving in free-flowing conditions, before stops and delays. Add time for fuel, food and rest breaks on any real trip.

Why is the driving distance longer than the straight-line distance?

Because roads follow terrain, junctions and street patterns rather than the direct great-circle line, which adds 36 miles — about 25 percent — on this pair.

How This Page Was Calculated

Coordinates come from the U.S. Census Bureau Gazetteer files, straight-line distance from the haversine formula, and driving figures from OpenStreetMap routing via OSRM where a measured route is published, or from our documented estimate (straight line × 1.25, time at 50 mph) where it is not. The full method, including its limits, is set out on our methodology page, and the companion guide to straight-line versus driving distance explains the concepts in plain language.

Sources: Coordinates: U.S. Census Bureau Gazetteer files; driving data: OpenStreetMap/OSRM — retrieved October 2026.