About Us


Guiding Projects Through Cultural Compliance Process

Plateau Archaeological Investigations, LLC conducts archaeological and cultural resource contracting and consulting services in eastern Washington, northern Idaho, and eastern Oregon. Our clients include federal and state agencies, counties, municipalities, utilities, engineering firms, and private organizations. By knowing and understanding the region we work in and the concerns of regional interested parties, we are able to focus our efforts toward providing solutions to specific concerns. Our reports satisfy the requirements of any funding agencies, state departments and agencies, and any Tribal entities who may comment.

Meet Compliance Requirements
Cost Effective
Ensure Efficiency
Knowledgeable Staff
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Shovel Probes Dug in 2021
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Acres Surveyed in 2021
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Miles Driven in 2021


Sprague Wastewater Lift Stations

The City of Sprague is proposing to refurbish a wastewater lift station and to construct an additional wastewater lift station.

Curlew Lake Private Development

After an archaeological data recovery from a known site near Curlew Lake in 2008, it was determined that the…

Oroville Street Realignment

The City of Oroville proposed a project to build a connector street between Jennings Loop Road and Bob Neil Road that…

Olympia-Grand Coulee Transmission Line

The Bonneville Power Administration proposes to replace worn insulators and improve associated…

What People Say

“It has been a pleasure to have Plateau Archaeological Investigations provide cultural resource reports and monitoring on our construction projects. They have worked well with our inspectors, contractors, and clients. In providing cultural resource monitoring, Plateau has been responsive, professional, and worked to complete the monitoring in accordance with the requirements, while minimizing the impact to the pace of construction. I look forward to continuing to work with Plateau on future projects.”
Jamin Ankney
P.E. Gray & Osborne, Inc.

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