Indian Rock Survey

Indian Rock Survey

Klickitat County Highpoint, Washington

Dec 7, 2025

Results: 5851.5ft +/-1.1ft NAVD88.

I was looking for a peak to survey on the weekend in WA, and Indian Rock, the Klickitat county highpoint had some interesting surveying history. There’s a USGS benchmark on the southern end of the peak, that had been mistakenly considered the highpoint in the past. But benchmarks aren’t necessarily put exactly on summits. To add to the confusion, the USGS quad for the area has the 5823ft benchmark labeled Indian Rock, and also has another point farther north on the summit labeled Indain Rock. This is next to a surveyed point 5819T.

Based on information from peakbagger.com, on October 11th, 2009, Edward Earl, Eric Noel, and Greg Slayden used a hose level and found that a rock outcrop near the southern benchmark was actually 6ft taller than the highest rocks in the benchmark area.

According to peakbagger, “on October 18th, 2009, Bob Bolton, Don Nelsen, and Ardith Bowman visited the area with a large sighting level and telescoping pipe segments. They concluded that the 5819 elevation near the Pinnacle is for a boundary marker, not the top of the Pinnacle. They measured the top of the Pinnacle to be about 5850 feet and clearly the highest point in the area.”

Also according to peakbagger, ” on October 8th, 2010, Ken Jones and Ken Russell visited the area with a professional surveyor’s level and confirmed the previous survey, putting the Pinnacle at 5845 feet and, again, clearly showing it to be the highest point on the mountain.”

Based on these surveys, the northernmost point labeled “Indian Rock” in the summit area is the true summit, and is approximately 5845ft – 5850ft. This is referred to by peakbaggers as “The Pinnacle”.These measurements were taken relative to the quad numbers, so are in NGVD29.

In 2022 LiDAR measurements were taken of the area, and they were published in 2024. LiDAR data is reported in NAVD88 datum, which is the current modern standard. The highest ground returns showed the Pinnacle 5838.0ft and the benchmark on the south 5830.6ft. Lidar data missed the sharp outcrop near the benchmark, but based on the hose level relative measuremets this meant the Outcrop is 5836.6ft.

This LiDAR data put the Outcrop and the Pinnacle within error bounds of LiDAR measurements, which are +/-1.7ft for open rocky peaks and +/-4.8ft for peaks covered in vegetation based on research I’ve published.

I figured it would be fun to take GNSS measurements to resolve any possible uncertainty and ideally get each elevation to the nearest inch.

On Sunday morning I met Katherine Cusumano at Satus Pass and we rode up Ski Lodge Road in my truck to snowline at 5000ft. That’s where the road started getting rough anyways, so we parked there.

We hiked up the road and the conditions were a bit different than I’d expected based on the forecast. The snow got around shin deep and it started raining and snowing with high winds. I had originally hoped to survey both the Outcrop and the Pinnacle for an hour each. But I decided to downgrade to just the Pinnacle given the conditions.

After 1.5 hours we reached the Pinnacle and scrambled up the icy west side into high wind and snow/rain. I quickly mounted the DA2 on the summit and started logging data, with my phone in a ziplock bag. The wind was high enough to push the tripod over, so I knelt next to it holding it down in place.

After about 15 minutes I decided to log the data and retreat, since I was losing feeling in my fingers. That would at least get 1ft accuracy, but not as good as a one hour measurement would have gotten. We aborted plans to survey the Outcrop and instead retreated to the truck and drove out.

I processed the results with TrimbleRTX and found an elevation 5851.5ft +/-1.1ft NAVD88. This was significantly higher than the highest ground return on LiDAR. There were unclassified returns from LiDAR close to this elevation on the Pinnacle, but it was difficult to know in advance if they were rock or vegetation, since there are tree branches overhanging the summit. This is one reason why ground surveys are important.

If you convert the Oct 18, 2009 survey to NAVD88, you get 5853.9ft. If you convert the Oct 8, 2010 survey to NAVD88, that would give 5848.9ft. These were measured relative to surveyed points on the quads, so there may have been some errors on the quad – surveyed points.

In conclusion, the Oct 8, 2010 survey established that the Pinnacle is the highest point on Indian Rock, and is higher than the benchmark and the Outcrop. The Dec 7, 2025 survey found the absolute elevation of the Pinnacle as 5851.5ft +/-1.1ft NAVD88.

 

 

 

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