Mosier is a city along the Columbia River in Wasco County, Oregon, United States.

The building now known as the post office was at that time the bank, and the original safe is still intact on-site.

Eleven cars derailed and at least one caught on fire, only 20 feet away from the city's sewage treatment facility.

[6] Eighteenmile Island is located a half-mile downstream of the city in the Columbia River.

This region experiences warm (but not hot) and dry summers, with no average monthly temperatures above 71.6 °F.

There were 250 housing units at an average density of 531.9 per square mile (205.4/km2).

37.4% of all households were made up of individuals, and 11.4% had someone living alone who was 65 years of age or older.

27.4% of all households were made up of individuals, and 8.5% had someone living alone who was 65 years of age or older.