# Tumtum Mountain

- **Country:** United States
- **Coordinates:** 45.934140, -122.336950
- **Age:** Pleistocene
- **Topo:** USGS Yale Dam
- **Type:** Lava dome
- **Range:** Cascade Range
- **Geology:** Dacite
- **Location:** Clark County, Washington, US
- **Elevation:** 2004 ft
- **Etymology:** Chinook Jargon
- **Prominence:** approx. 880 ft
- **Elevation M:** 610.8
- **Translation:** Heart
- **Volcanic Arc:** Cascade Volcanic Arc
- **Easiest Route:** Abandoned logging road to summit
- **Last Eruption:** 70,000 years ago

Tumtum Mountain is a small, highly-symmetrical volcanic cone in Washington, United States. Located in northern Clark County at the easternmost end of Chelatchie Prairie, it rises to an elevation of , about above the flat prairie. This Pleistocene dacite lava dome is part of the Cascade Volcanic Arc, and with an age of only about 70,000 years, Tumtum Mountain is the youngest and westernmost volcano in the Cascades of Washington state.

![Photo of Tumtum Mountain](https://upload.wikimedia.org/wikipedia/commons/b/b0/Tumtum_Mountain_West_View.jpg)

**Source:** https://en.wikipedia.org/wiki/Tumtum_Mountain (Wikipedia, CC BY-SA)