Upper Arrow Mill Property
IndustrialHumboldt County, California · CAISO
At a glance
Upper Arrow Mill Property is an industrial datacenter candidate site in Humboldt County, California, scoring 41.4/100 DC Readiness — 38th of 156 scored sites in the county. It sits in the CAISO grid region and the PACIFIC GAS & ELECTRIC CO. service territory, where interconnection has averaged 7.6 years from request to operation.
Power & interconnection
Speed to power
Deep queue and long historical waits — plan for a multi-year interconnection timeline and engage the utility early.
Connectivity
Site characteristics
Risk & environment
Location context
Regulatory climate
No notable statewide DC restriction on record; confirm local zoning and utility tariffs.
Site location
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How does Upper Arrow Mill Property compare with other sites in Humboldt County?
Upper Arrow Mill Property ranks 38th of 156 scored candidate sites in Humboldt County. Its 41.4/100 is roughly in line with the county average of 41.4. It is roughly in line with the California average of 45.4 and about 22% below the national average of 53.2.
Against the California average, its strongest sub-score is natural hazard (52 vs 51) and its weakest is fiber connectivity (55 vs 66). Power and speed to power each carry 20% of the composite score, fiber 12%, water 7% and hazard 6%.
How close is Upper Arrow Mill Property to power, fiber and other datacenters?
For connectivity, the nearest internet exchange facility is Hemlock Plaza at 54 miles. 4 fiber providers report service at the location in FCC broadband data. The closest operating datacenter on record is Hemlock Plaza, 54 miles away.
What are the flood, water and hazard risks at Upper Arrow Mill Property?
At the county level, FEMA's National Risk Index rates Humboldt County "Relatively High".
Full DC Readiness breakdown
All 13 weighted sub-scores (0–100) behind the composite DC Readiness score.
Nearby comparable sites
Other scored datacenter candidate sites in Humboldt County, ranked by DC Readiness.
| Site | Type | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|
| HUMBOLDT BAY | Substation-Adjacent | 115 kV | 100 MW | 7.6 yrs | 47.6 |
| EC Near Humboldt Bay | Greenfield | — | — | 7.6 yrs | 47.2 |
| ARCATA | Substation-Adjacent | 115 kV | 100 MW | 7.6 yrs | 46.7 |
| BRIDGEVILLE | Substation-Adjacent | 115 kV | 100 MW | 7.6 yrs | 46.6 |
| HUMBOLDT | Substation-Adjacent | 115 kV | 100 MW | 7.6 yrs | 46.5 |
| OZ Humboldt | Greenfield | — | — | 7.6 yrs | 44.8 |
| LOUISIANA PACIFIC | Substation-Adjacent | 69 kV | 50 MW | 7.6 yrs | 44.7 |
| RIO DELL | Substation-Adjacent | 69 kV | 50 MW | 7.6 yrs | 44.7 |
Upper Arrow Mill Property: common questions
What is the DC Readiness score of Upper Arrow Mill Property?
Upper Arrow Mill Property scores 41.4/100 on the GridCensus DC Readiness scale, rated fair. It ranks 38th of 156 scored sites in Humboldt County. The Humboldt County average is 41.4 and the California average is 45.4.
Which electric utility serves Upper Arrow Mill Property?
PACIFIC GAS & ELECTRIC CO. (investor owned) holds the retail service territory that contains the site; its holding company is PACIFIC GAS & ELECTRIC CORPORATION.
What grid region is Upper Arrow Mill Property in?
Upper Arrow Mill Property is in the CAISO region. Projects interconnecting there have averaged a 7.6-year wait from queue request to operation.
How far is Upper Arrow Mill Property from an internet exchange?
The nearest internet exchange facility is Hemlock Plaza, about 54 miles away; 4 fiber providers report service at the location.
Related pages
About this data
Source: GridCensus composite of HIFLD transmission and substation data, EIA, FEMA National Risk Index, FCC broadband data, PeeringDB and ISO interconnection queues, as published October 10, 2026 — GridCensus refreshes it monthly. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “Upper Arrow Mill Property, Humboldt County, CA”, https://gridcensus.com/datacenter-sites/california/humboldt-county/upper-arrow-mill-property-cc4b810d (data as of October 10, 2026).
Dataset updated . Screening estimates derived from public data sources.
Figures are screening estimates derived from public infrastructure data. Catalogued capacity reflects theoretical candidate capacity, not deliverable or committed interconnection. Confirm all values with the utility, ISO, and on-the-ground due diligence.
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