Monarch Data Center campus (Mason Valley)
Copia Power wants to build a 1,000 megawatt data center campus with its own gas power plant near Yerington. The county approved a key rezoning in August 2026. Two Paiute tribes and the Sierra Club oppose it, mainly over groundwater.
Where things stand: County approved tentative rezoning 3-1 on Aug. 6, 2026. Final plan, state permits and land purchase still needed. Tribes plan to sue.
🕒 Latest update (Aug 6, 2026): County commissioners approved the tentative rezoning 3-1 (one abstained).
What we know
- 📍 WhereMason Valley, about 8 miles north of Yerington, east of US 95A, Lyon County
- 🏢 CompanyCopia Power
- 🌳 Size505 acres
- ⚡ Power it needs1,000 megawatts (about as much as 800,000 homes)
- 🔌 Where the power comes fromNew 500 MW gas power plant and 500 MW battery on site until NV Energy can serve it; gas plant may keep running after.
- 🗼 New power linesYes
- 💧 Waterexisting farm water rights (groundwater); needs State Engineer approval
- ❄️ Coolingmostly closed-loop, air-cooled (company claim)
- 💵 Cost$15.3 billion
- 💸 Tax breaksCopia says it will not seek tax breaks.
❓ Still unanswered
Nobody has answered these in public yet. Can you help find out?
- How much water will Monarch really use? Copia's numbers range from under 100 to under 800 acre-feet a year. 🙋 I'll find out
- Will the State Engineer let farm water rights move to the data center? 🙋 I'll find out
- Have the Walker River Paiute or Yerington Paiute tribes filed a lawsuit? 🙋 I'll find out
- When will the final plan go to the county board? 🙋 I'll find out
What happened so far
- Dec 2025County commissioners approved a master plan change 4-1 for the site.
- July 14, 2026Planning commission voted 4-3 to recommend the rezoning.
- Aug 6, 2026County commissioners approved the tentative rezoning 3-1 (one abstained).
Local votes and rules
🗺️ Zoning change
Lyon County commissioners voted 3-1 (one commissioner stepped aside) to approve the planned unit development rezoning for the Monarch Data Center and its gas power plant near Yerington. Copia Power has one year to file the final plan and still needs state permits. The Walker River Paiute and Yerington Paiute tribes said they would fight the decision in court.
✅ Approved
Lyon County's Planning Commission voted 4-3 to send the 1-gigawatt Monarch Data Center rezoning on to the County Commission.
🗺️ Zoning change
Lyon County commissioners voted 4-1 to change the master plan for the Monarch Data Center site in Mason Valley from farmland (Agriculture) to Specific Plan. This did not approve building anything; a rezoning was still needed.
An aerial photo of the area.
Where this comes from
- Monarch data center zoning change approved after hours of testimony · Fernley Reporter · Aug 12, 2026
- A massive data center in rural Nevada is one step closer to being built · The Nevada Independent · Aug 10, 2026
- Lyon County Commissioners approve Monarch Data Center · KOLO 8 · Aug 6, 2026
- No land? No problem: Why many Nevada data centers don't own the land they're asking to develop · The Nevada Independent · July 2026
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