Warren County, Illinois: Power, Data Centers and the Local Economy
Home to Monmouth Township, Monmouth and Roseville Township
No data center or power plant project is on record in Warren County, but the national build-out still reaches it through its utility bill, its labor market and the projects next door. Warren County is home to Monmouth Township, Monmouth, Roseville Township and Spring Grove Township. Next door, Mercer County has 1 data center. Electrical contractors employ 10, up 25.0% since 2019 against up 3.9% statewide, at an average $52,130 a year. 35 MW of that came online in 2019 or later, mostly solar. Its power plants have 35 MW of capacity, 100% of it solar.
Cities and towns in Warren County
Warren County is home to Monmouth Township, Monmouth, Roseville Township and Spring Grove Township.
- Alexis also extends into Mercer County.
Unincorporated communities (governed by the county): Cameron.
Residents are 2025 Census estimates for the part of each city, town or township inside this county. Census publishes no annual estimate for unincorporated communities.
What changed in Warren County
1st = the most. Ranks cover counties with a value on record.
| Measure | Then | Now | Change | Rank in Illinois |
|---|---|---|---|---|
| Population (2020 → 2025) | 16,837 | 16,222 | ▼ 3.7% | 65th of 102 by size |
| Total jobs (2019 → 2025) | 6,396 | 6,346 | ▼ 0.8% | 53rd of 102 by growth |
| Average annual pay (2019 → 2025) | $37,276 | $46,233 | ▲ 24.0% | — |
| Electrical contractor jobs (2019 → 2025) | 8 | 10 | ▲ 25.0% | — |
| Unemployment rate (2019 → August 2026) | 4.2% | 3.6% | ▼ 0.6pts | — |
| Generating capacity added since 2019 | — | 35 MW | — | |
| Generating capacity retired since 2019 | — | 0 MW | — |
Unemployment was 3.6% in August 2026, against 4.2% in 2019. Ameren Illinois Company is the largest utility serving Warren County, one of 2 with territory here. Its residential customers paid an average 15.26¢/kWh in 2024. Employers here counted 6,346 jobs in 2025, down 0.8% from 2019. 16,222 people live here, down 3.7% since 2020.
Who powers Warren County
Net change in operating capacity since 2019: +35 MW. Colors follow the fuel legend above.
Utilities with service territory in Warren County
| Utility | Ownership | Service | Residential customers (systemwide) | Residential price, 2024 | Commercial share of sales |
|---|---|---|---|---|---|
| Ameren Illinois Company | Investor Owned | Bundled | 1,060,894 | 15.26¢ | 28% |
| McDonough Power Coop | — | — | — | — | — |
Customer counts, prices and sales shares cover each utility's whole system in the state, not only this county. Commercial sales include data centers.
Operating power plants 1
| Technology | Capacity | Share |
|---|---|---|
| Solar | 35 MW | 100% |
| Largest plants | Owner | Technology | MW | Since |
|---|---|---|---|---|
| Earp Solar, LLC | Birch Creek Power, LLC | Solar | 35 MW | 2024 |
The Warren County labor market
| Industry (2025) | Jobs | Average pay | Concentration vs U.S. |
|---|---|---|---|
| All industries | 6,346 | $46,233 | 1.00 |
| Electrical contractors | 10 | $52,130 | 0.22 |
Concentration is the BLS location quotient: 1.0 means the industry holds the same share of local jobs as it does nationally. Industry rows count private employers; cells BLS suppresses are left out.
Data centers and local rules in Warren County
No data center, local measure or delayed project is on record in Warren County. Illinois has 28 local measures on record statewide.
Warren County and its neighbors
Of the 5 counties that border Warren County, Mercer County carries the most build-out activity: data centers, planned generation and operating plants combined.
| County | Population | Jobs since 2019 | Operating MW | Planned MW | Data centers | Local measures |
|---|---|---|---|---|---|---|
| Warren County | 16,222 | ▼ 0.8% | 35 MW | — | — | — |
| Fulton County | 32,901 | ▲ 4.6% | 156 MW | — | — | — |
| Henderson County | 5,984 | ▲ 8.8% | 1 MW | — | — | — |
| Knox County | 47,767 | ▼ 2.4% | 16 MW | 5 MW | 1 | — |
| McDonough County | 25,916 | ▼ 7.2% | 171 MW | 10 MW | — | — |
| Mercer County | 15,229 | ▲ 1.0% | 10 MW | 42 MW | 1 | — |
More of Illinois
Warren County, answered from the record
Who provides electricity in Warren County, Illinois?
2 utilities have service territory in Warren County in the EIA-861 2024 report: Ameren Illinois Company, McDonough Power Coop. The largest, Ameren Illinois Company, charged residential customers 15.26¢/kWh on average in 2024.
What power plants are in Warren County?
1 operating plant with 35 MW of capacity. The largest is Earp Solar, LLC (35 MW, solar).
Are there data centers in Warren County?
The SAVRN Data Center Map has no data center in Warren County. The nearest activity on record is next door in Mercer County.
Is Warren County adding jobs?
Employers counted 6,346 jobs in 2025 against 6,396 in 2019 (-0.8%, BLS QCEW).
Does Warren County have a data center moratorium?
No county-level measure is on record for Warren County. Illinois has 28 local measures statewide, listed on the state page.