Sherman County is the smallest-population county in Oregon. Moro sits at the county seat, with Wasco, Grass Valley, Rufus, and Biggs Junction filling out the small downtowns scattered across the Columbia Plateau wheat country. The economy is built on dryland wheat farming, ranching, and the wind-energy infrastructure that runs across the plateau and along the Columbia River. Excavation work in Sherman County is paced by long haul distances, basalt-and-loess subgrade, and a thin local contractor pool.
Cojo Excavation & Asphalt extends out to Sherman County through our eastern Oregon I-84 corridor operations. This guide covers what local conditions mean for site-prep cost, the project mix typical in the area, and what to look for in a quote when most of the bidders will be coming from outside the county.
Moro, Wasco, Grass Valley, Rufus -- The County Map
Moro is the county seat -- a small downtown grid at the center of the wheat country with a population of about 320. Wasco sits north of Moro on Highway 206, a similar-scale town on the rail line. Grass Valley to the south is the smallest of the four main communities. Rufus and Biggs Junction sit up on I-84 along the Columbia, with Rufus the larger commercial node and Biggs the I-84 / US-97 interchange town.
Most of the excavation work in Sherman County is rural -- ranch and farm access roads, grain-storage and equipment-shop pads, wind-farm foundation work, and occasional small-commercial pads in the I-84 corridor towns. Residential excavation volume is low simply because the population is low.
Columbia Plateau Subgrade -- Basalt and Loess
Sherman County sits on the Columbia River Basalt Group with windblown loess on top. The loess layer is typically 1 to 5 feet thick and compacts well with crushed-rock import. Below the loess, you hit basalt -- sometimes weathered to a manageable depth, sometimes solid bedrock that needs rock-hammer or rock-saw work for any cut deeper than a few feet.
The practical implication: footing excavation, utility trenches deeper than 4 feet, and any pad cut on slope often involves rock work. A real Sherman County quote should name rock-encounter contingency as a separate line item with an hourly rate, not bury it as a generic add-on. Surface work that follows the dirt -- asphalt paving in Sherman County and Sherman County parking lot striping -- depends on stable base prep over that basalt-and-loess subgrade.
Wind-Farm and Industrial Excavation
The Columbia Plateau is heavily developed with wind energy. Sherman County has a substantial wind-farm footprint, and the support infrastructure -- substation pads, access roads, foundation excavation, underground collector cable trenches -- generates a meaningful share of the county's excavation work. Wind-farm projects involve specialty subcontracting paths, prevailing-wage requirements on certain federal-funded scopes, and tight finish-grade tolerances around foundation pads.
For private owners outside that wind-farm economy, the relevant point is that local contractor availability tightens whenever a wind project is in the build phase -- crews and equipment move toward the higher-margin wind work, which pushes residential and small-commercial quote lead times out.
Frost Depth and the Eastern Oregon Calendar
Sherman County frost depth runs 24 to 36 inches across most of the populated area. Footing excavation has to go below frost line, which means deeper cuts than valley work for the same building footprint. The seasonal work window for major site-prep is roughly April through October, with the most reliable dry stretch from late May through September.
I-84 corridor sites near the Columbia (Rufus, Biggs) often pick up earlier in spring than south-county wheat-country sites where colder mornings persist later. Owners planning a 2026 build should book in late winter for summer crews. For pricing context on the variables that shape eastern Oregon work, see our excavation cost factors in Oregon breakdown.
Wet-Season Strategy
Sherman County is dry by Oregon standards -- annual precipitation runs 10 to 15 inches depending on elevation. The constraint is frost and wind, not rain. Crews can usually work into November and pick back up in March for utility-trench and pad-prep work in the lower-elevation corridor. Snow events are common December through February but typically clear within a week.
Long Haul and What It Means for Pricing
Sherman County's small population and basalt geology mean limited local aggregate sources. Crushed-rock often hauls from pits in The Dalles, Hermiston, or further. Spoils disposal usually means a haul to Wasco County or beyond. These haul costs are real, and they belong in writing on the quote.
A contractor coming from outside the county also has equipment mobilization to factor in. A skid steer and operator coming from Hood River to Moro is 90 miles each way -- that mobilization belongs on the quote as well. Contractors who skip these line items are either eating the cost or planning to surface it as a change order. For pricing context on the variables that shape excavation cost, see our driveway excavation cost in Oregon guide.
Common Sherman County Project Types
The mix we see across Sherman County tends to include:
- Wheat-farm shop and equipment-storage pad excavation, 2,000 to 8,000 sq ft.
- Ranch and farm access-road grading, often miles of work at a time.
- Wind-farm support infrastructure -- substation pads, collector trenches, foundation cuts.
- I-84 corridor small-commercial pads (Rufus, Biggs Junction) for fuel and travel-stop work.
- Footing excavation to 36-inch frost depth for new construction.
Sherman County Excavation Cost Ranges
Eastern Oregon excavation pricing reflects long aggregate haul distances, deeper frost-depth requirements, rock-encounter contingency on basalt sites, and a thin local contractor pool that keeps mobilization and labor pricing firm.
Industry Baseline Range
| Project Type | Typical Range |
|---|---|
| Residential driveway excavation (600 to 1,200 sq ft) | $4,500 to $11,000 |
| Farm-shop or equipment-storage pad (2,000 to 8,000 sq ft) | $9,500 to $40,000+ |
| Ranch access-road grading, per linear foot | $8 to $25 |
| Utility trench, per linear foot | $35 to $100 |
| Spoils haul-off, per cubic yard | $55 to $115 |
| Rock-hammer time, basalt sites | $225 to $425 per hour |
Current Market Reality
2026 Sherman County pricing pushes the upper end of baselines. Aggregate haul, equipment mobilization, basalt rock-encounter, and frost-depth-driven cut depth all stack into the same quote. Quotes well below the lower bound usually have not honestly accounted for at least one of those four factors. The honest read is that Sherman County excavation is more expensive per cubic yard than valley work, and that is structural -- not contractor markup.
Booking a Sherman County Site Walk
Cojo Excavation & Asphalt covers Moro, Wasco, Grass Valley, Rufus, Biggs Junction, and the rest of Sherman County. We do site walks before we quote -- including a basalt-encounter assessment where the cut depth makes it relevant -- and our scope sheet names soil type, frost-depth target, drainage handling, base-rock volume, and rock-hammer contingency. Contact us to schedule. For our broader range of services, the excavation services page covers our crew, equipment, and licensing.