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Grass Mountain (OR)

Grass Mountain (OR)

Grass Mountain (OR)

Page Type: Mountain/Rock

Location: Oregon, United States, North America

Lat/Lon: 44.42420°N / 123.6717°W

Object Title: Grass Mountain (OR)

County: Benton

Activities: Hiking

Season: Spring, Summer, Fall

Elevation: 3603 ft / 1098 m


Page By: Dean

Created/Edited: Feb 22, 2007 / Mar 30, 2009

Object ID: 272222

Hits: 10897 

Page Score: 89.01%  - 28 Votes 

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Grass Mountain
Lookout site


Grass Mountain is one of Oregon's 73 prominence peaks, coming in at #56 on the list with 2163 feet of prominence. It is not a place that appears grassy but who knows, the mountain may be named after some guy named Grass or it could be a place where people were caught smoking some. Prominence peak chasing is a fun pursuit and if you are at all into this strange form of peakbagging, you will find the information contained here to be helpful.
Leave your ice axe, crampons and rope at home but in late winter or early spring you might want to bring some snowshoes.

Grass Mountain is located southwest of Corvallis and not all that far from Mary's Peak, in the coastal mountains. It is bordered on the south by the Alsea River and on the north by the Yaquina River. It isn't a difficult hike but does entail close to 6 miles of hiking with close to a thousand feet of elevation gain so it is a good hike to take your 8 year old grandson on (which I did)

Typical of the area, much of the hike is through forested areas and only breaks out into a grassy area (maybe the source of the mountains name) near the summit. Trees block the views in any direction other than to the south but at one time a lookout once stood watch over the area. There are still some concrete footings in the area. Just north of the concrete footings, a rock appears to be the highest point. Right next to it I placed a plastic jar register with memo pad and pen. I couldn't find the main benchmark but a witness benchmark can be found on the big rock I referred to.

Consider combining this one with either Mary's Peak or Prairie Mountain, both of which are Oregon Prominence peaks.

Getting There

Grass Mountain
The gate
From I-5, head into Corvallis and take the turnoff for the town of Alsea on highway 34. This is a road used by many to get to the Oregon Coast and passes Mary's Peak state park as you head for Alsea. The road you will need to watch for is 1.7 miles west of Alsea and it takes off uphill to the right. (TOPOZONE Help) Make a copy of the topozone map and study it so you can make the drive easier. About a mile up the road, the road forks, the left going to a private holding so take the right. It is the first one on the topozone map linked to earlier.

The road is in great shape but may have logging traffic on it during the weekdays so be forewarned and be watchful. Another fork comes at the 3.5 miles (from highway 34)and stay right. The road gets very windy and will gain and then lose some elevation before you get to the next important road junction, a T in the road (TOPOZONE Help)Turn left but mark in your mind where you turned off from as you could miss this on your way back down. My odometer said it was 9.7 miles to this point but odometers vary and this will put you in the ball park.

Stay on the road for .8 mile watch for an older road on the left which leads to a gate where you begin your hike. At one time this was the only road but a newer segment that continues on uphill can confuse you. The older road tends to go downhill to this point (TOPOZONE Help) so a GPS can prove very helpful here. The gate is reached in two tenths of a mile after you turn off of the newer section of road so if you drive further than that without seeing the gate, you are on the wrong road. I hope that is crystal clear. The route will be covered a bit later.

Red Tape and weather (Alsea Oregon)

There is no red tape to deal with on this hike but it might be wise to park so as to not block the gate even though the condition of the road beyond the gate has a couple of rather large wash outs indicating that this road is no longer used.


You could actually car camp right near the gate but this hike is an easy day hike and most likely the need for camping would be limited. Mary's Peak, which is on the way, has a campground. You could combine Mary's Peak, Grass Mountain and Prairie Mountain, all Oregon P2K peaks on the same day.
Mary's Peak Campground

Grass Mountain

The route

Grass Mountain
There is no need to provide a separate page for the route as it is mainly a road walk past the gate. See Dennis Poulin's map for an overview of the road.

Walk past the gate as it gradually gains elevation to this "T" junction.
. Go right and continue walking up the road and when you encounter a big yellow post (TOPOZONE Help) in the middle of the road, go past it, 
Grass Mountain
Yellow Post
down into a wash out and back up onto the road as it continues once again to head up the hill. You'll pass a road that comes in from the right so stay left as the road goes up the hill into an interesting forested area.
Grass Mtn
This was my favorite part of the whole hike and you will need to step around and over some deadfall that has fallen onto the old lookout road. Continue on up the road until you reach a sharp bend and then the road will will swing northeast towards the old lookout area. The track is becoming overgrown and you may need to duck a few times but soon you will come out of the overgrown section and find a large grassy area just off to the right.

Then the old road will reach an area where you leave the road and will find the old concrete footings. Just beyond the footings, a rock that contains the witness benchmark and has a register laying nearby will culminate your effort to add this prominence peak to your collection if you are chasing the prominence peaks. My grandson felt it was quite the adventure to reach the top but was somewhat disappointed to find that it wasn't a sharp pinacle with drop offs on every side. I think he enjoyed the grassy area the most with its views over to Prairie Peak to the south.

Roundtrip: 5.4 miles Elevation gain: 1000 feet Grandson's pace: 3 hours

Grass Mountain
The top?

Grass Mountain Lookout and Hayden Bridge

A State Forestry fire lookout tower was built on top of Grass Mountain in 1935. It was a 40 foot wooden tower structure with a 14x14 cab. In 1955, the BLM clearcut approximately 7.5 acres of forest lands immediately around the tower to improve visibility. The tower was decommissioned and dismantled in 1968. All that remains are some concrete footings and rebar amidst the fern like undergrowth that covers the rounded summit.

If anyone who reads this knows anything additional about this lookout or has a picture of it, please let me know.

While in the area, be sure and check out this local attraction,
The Hayden Bridge.

Grass Mountain isn't observable from highway 34 but you do get views of it from Prairie Peak (south) and from Mary's Peak (east). This is a forested area and historic grazing probably accounts for the high percentage of non-native grasses on the open meadows that are found near the peak.

I give credit to Dennis Poulin for the majority of all the pictures that are posted on thispage.

Note: Consider doing this mountain on the same day along with Prairie Peak and since Mary's Peak in also nearby and is on the way from Philomath on highway 34, you could possibly get all three prominence peaks that are in the area.


Grass MtnGrass MountainGrass Mountain seen from Prairie PeakGrass MountainGrass Mtn Witness BM (OR)Grass MountainGrass Mountain
Grass MountainGrass Mountain