Mercer CountyPower Outage History
What this grade means
Bottom 20% least reliable nationally — frequent and/or long outages. This county ranks in the least reliable fifth of all US counties in our dataset: some combination of frequent outages, long restoration times, or customers affected puts it near the bottom nationally. Backup power is worth prioritizing here rather than treating it as optional.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Feb 12, 2019 | 40 hrs | 6,907 (68%) | Unnamed event |
| Oct 22, 2015 | 3 hrs | 6,308 (62%) | Unnamed event |
| Jan 2, 2019 | <1 hr | 6,182 (61%) | Unnamed event |
| Dec 28, 2015 | 57 hrs | 5,927 (59%) | Tornado |
| Jan 1, 2021 | 2 hrs | 5,250 (52%) | Winter Storm |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Mercer County, Illinois that day.
Over the 12 years from 2014 to 2025, Mercer County recorded 546 distinct power outage events, averaging 3.9 hours per event.
The single worst outage on record in Mercer County started February 12, 2019, lasting 40 hours and leaving up to 6,907 customers without power (68% of the county) at its peak.
June has historically been the worst month for outages in Mercer County, with 64 events recorded during that month across the dataset.
Based on this history, Mercer County earns a Reliability Grade of F, placing it in the 11th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Illinois
Counties with the closest reliability grade and national percentile to Mercer County.
| County | Grade | National percentile |
|---|---|---|
| Stark County | F | 13th |
| Henderson County | F | 19th |
| Marshall County | D | 22nd |
| Putnam County | D | 26th |
| Edgar County | D | 29th |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
FAQ
How often does power go out in Mercer County?
Between 2014 and 2025, Mercer County recorded 546 outage events, averaging 3.9 hours each.
What is Mercer County's reliability grade?
Mercer County has a Reliability Grade of F, in the 11th national percentile.
What was the worst power outage in Mercer County?
The worst outage on record started February 12, 2019, lasting 40 hours and affecting up to 6,907 customers.