Monroe County, Illinois: Power, Data Centers and the Local Economy
Home to Waterloo, Columbia and Valmeyer
No data center or power plant project is on record in Monroe County, but the national build-out still reaches it through its utility bill, its labor market and the projects next door. Monroe County is home to Waterloo, Columbia and Valmeyer. Next door, St. Louis County, Missouri, has 7 data centers and 648 MW of planned generation. Construction employs 549, down 5.2% since 2019. 8 MW of that came online in 2019 or later, mostly natural gas. Its power plants have 38 MW of capacity, 57% of it natural gas.
Cities and towns in Monroe County
Monroe County is home to Waterloo, Columbia and Valmeyer.
- Columbia also extends into St. Clair County.
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 Monroe County
1st = the most. Ranks cover counties with a value on record.
| Measure | Then | Now | Change | Rank in Illinois |
|---|---|---|---|---|
| Population (2020 → 2025) | 34,961 | 34,840 | ▼ 0.3% | 40th of 102 by size |
| Total jobs (2019 → 2025) | 8,456 | 8,577 | ▲ 1.4% | 36th of 102 by growth |
| Average annual pay (2019 → 2025) | $36,660 | $51,694 | ▲ 41.0% | — |
| Construction jobs (2019 → 2025) | 579 | 549 | ▼ 5.2% | 51st of 56 by growth |
| Electrical contractor jobs (2019 → 2025) | 90 | 30 | ▼ 66.7% | — |
| Unemployment rate (2019 → August 2026) | 2.9% | 2.5% | ▼ 0.4pts | — |
| Generating capacity added since 2019 | — | 8 MW | — | |
| Generating capacity retired since 2019 | — | 0 MW | — |
Ameren Illinois Company is the largest utility serving Monroe County, one of 4 with territory here. Its residential customers paid an average 15.26¢/kWh in 2024. Employers here counted 8,577 jobs in 2025, up 1.4% from 2019. Unemployment was 2.5% in August 2026, against 2.9% in 2019. 34,840 people live here, down 0.3% since 2020. Electrical contractors employ 30, down 66.7% since 2019 against up 3.9% statewide, at an average $77,021 a year.
Who powers Monroe County
Net change in operating capacity since 2019: +8 MW. Colors follow the fuel legend above.
Utilities with service territory in Monroe 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% |
| Egyptian Electric Coop Assn | Cooperative | Bundled | 13,707 | 15.53¢ | 42% |
| Monroe County Elec Coop, Inc | — | — | — | — | — |
| City of Waterloo - (IL) | — | — | — | — | — |
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 |
|---|---|---|
| Natural gas | 22 MW | 57% |
| Petroleum | 17 MW | 43% |
| Largest plants | Owner | Technology | MW | Since |
|---|---|---|---|---|
| Waterloo | City of Waterloo - (IL) | Petroleum | 38 MW | 1946 |
The Monroe County labor market
| Industry (2025) | Jobs | Average pay | Concentration vs U.S. |
|---|---|---|---|
| All industries | 8,577 | $51,694 | 1.00 |
| Construction | 549 | $78,818 | 1.21 |
| Electrical contractors | 30 | $77,021 | 0.49 |
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 Monroe County
No data center, local measure or delayed project is on record in Monroe County. Illinois has 28 local measures on record statewide.
Monroe County and its neighbors
Of the 5 counties that border Monroe County, St. Louis 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 |
|---|---|---|---|---|---|---|
| Monroe County | 34,840 | ▲ 1.4% | 38 MW | — | — | — |
| Jefferson County MO | 233,132 | ▲ 3.4% | — | — | — | — |
| Randolph County | 29,921 | ▼ 9.4% | 1,504 MW | — | — | — |
| St. Clair County | 250,708 | ▼ 3.2% | 1,821 MW | 155 MW | — | — |
| St. Louis County MO | 990,911 | ▼ 3.4% | 34 MW | 648 MW | 7 | — |
| Ste. Genevieve County MO | 18,689 | ▲ 9.0% | — | — | — | — |
More of Illinois
Monroe County, answered from the record
Who provides electricity in Monroe County, Illinois?
4 utilities have service territory in Monroe County in the EIA-861 2024 report: Ameren Illinois Company, Egyptian Electric Coop Assn, Monroe County Elec Coop, Inc, City of Waterloo - (IL). The largest, Ameren Illinois Company, charged residential customers 15.26¢/kWh on average in 2024.
What county is Waterloo, IL in?
Waterloo is in Monroe County, Illinois. About 11,132 people live there (2025 Census estimate).
What county is Columbia, IL in?
Columbia is in Monroe County, Illinois. About 10,674 people live there (2025 Census estimate).
What power plants are in Monroe County?
1 operating plant with 38 MW of capacity. The largest is Waterloo (38 MW, petroleum).
Are there data centers in Monroe County?
The SAVRN Data Center Map has no data center in Monroe County. The nearest activity on record is next door in St. Louis County.
Is Monroe County adding jobs?
Employers counted 8,577 jobs in 2025 against 8,456 in 2019 (+1.4%, BLS QCEW). Construction went from 579 to 549.
Does Monroe County have a data center moratorium?
No county-level measure is on record for Monroe County. Illinois has 28 local measures statewide, listed on the state page.