The Town FilesSeneca, Illinois
Village in LaSalle County · population 2,353 (2020 Census) · spans 2 counties
- Median home
- $227,500
- Household income
- $86,830
- Jan low / Jul high
- 14° / 84°
- Snow a year
- 25 in
- Tornadoes ≤10 mi since 1950
- 14
- Median age
- 35.5
Seneca is a village of 2,353 people in LaSalle County, Illinois. The median home is worth $227,500, above the typical Illinois town ($156,600). It ranks better for a vacation home than 98% of Illinois towns, quieter than 77% of Illinois towns, easier by car than 77% of Illinois towns.
How Seneca ranks
Percentile among Illinois towns with at least 500 people on The Town Files lifestyle rankings. 50 is typical for the state; 90 means better than 90% of Illinois towns.
Homes and cost of living
The median home in Seneca is worth $227,500, above the typical Illinois town ($156,600). Homes cost about 2.6 times the median household income of $86,830, which is more affordable than 35% of Illinois towns. Median rent is $1,149 a month. 81.3% of households own their home.
| Housing | Seneca | Typical Illinois town |
|---|---|---|
| Median home value | $227,500 | $156,600 |
| Median rent | $1,149 | $960 |
| Median household income | $86,830 | $72,500 |
| Home value ÷ income | 2.6× | 2.2× |
| Homeownership | 81.3% | 76.6% |
| Median year built | 1976 | 1967 |
| Seasonal / vacation homes | 0.0% | — |
Who lives in Seneca
| People | Seneca | Typical Illinois town |
|---|---|---|
| Median age | 35.5 | 40.4 |
| Age 65 and over | 12.1% | 18.7% |
| Under 18 | 28.6% | — |
| Bachelor's degree or higher | 14.9% | 21.8% |
| Below the poverty line | 22.2% | 9.9% |
| Veterans | 11.2% | — |
| Born outside the U.S. | 2.0% | — |
| Work from home | 8.2% | 8.9% |
| Average commute | 26.2 min | 26.1 min |
| Homes with broadband | 93.5% | 90.4% |
Weather in Seneca
July highs average 84.0°F and January lows 14.2°F. About 39.0 inches of rain and melted snow fall a year, with 25.0 inches of snow (typical Illinois town: 24.2 in). Expect about 14 days a year at 90°F or hotter and 139 nights at or below freezing.
Tornadoes, storms and disasters
14 tornadoes have passed within 10 miles of Seneca since 1950, compared with 27 for the typical Illinois town. 4 rated (E)F2 or stronger. The strongest, an EF3, struck on February 28, 2017 about 7.4 miles from the town center and killed 2. Tornadoes within 10 miles have caused 2 deaths and 14 injuries since 1950. The most recent was on May 30, 2018.
Hail of 1 inch or larger has been reported within 10 miles 12 times; the largest was 3.75 inches on July 13, 2015.
Severe weather in LaSalle County since 1996
LaSalle County has been included in 20 federal disaster or emergency declarations since 1953, most often for flood, tornado, hurricane.
| Declared | Incident | Declaration |
|---|---|---|
| March 26, 2020 | Biological | DR-4489: Covid-19 Pandemic |
| March 13, 2020 | Biological | EM-3435: Covid-19 |
| November 26, 2013 | Tornado | DR-4157: Severe Storms, Straight-Line Winds, And Tornadoes |
| May 10, 2013 | Flood | DR-4116: Severe Storms, Straight-Line Winds, And Flooding |
| March 17, 2011 | Snowstorm | DR-1960: Severe Winter Storm And Snowstorm |
Jobs and pay in LaSalle County
LaSalle County had 39,242 jobs in 2024, paying an average of $58,537 a year. Unemployment was 5.8% in 2023; in Seneca itself the ACS puts it at 4%.
Public schools in Seneca
3 public schools with 848 students, about 10.1 students per teacher.
| School | Grades | Students | Per teacher |
|---|---|---|---|
| Seneca High School | 9-12 | 361 | 10.0 |
| Seneca Grade School North Campus | PK-4 | 274 | 9.8 |
| Seneca Elem School South Campus | 5-8 | 213 | 10.7 |
Towns near Seneca
- Marseilles, IL3.4 mi · 4,845 people · home $142,500
- Mazon, IL10.8 mi · 979 people · home $207,700
- Morris, IL11.2 mi · 14,163 people · home $247,400
- Dayton, IL11.4 mi · 528 people · home $271,000
- Ottawa, IL11.4 mi · 18,840 people · home $154,000
- Grand Ridge, IL12.1 mi · 515 people · home $158,700
- Sheridan, IL16.0 mi · 2,431 people · home $186,400
- Newark, IL16.3 mi · 973 people · home $241,100
Seneca questions
Is Seneca, Illinois a good place to retire?
On The Town Files lifestyle rankings, Seneca scores better for retirees than 65% of Illinois towns and quieter than 77%. 12.1% of residents are 65 or older (median age 35.5).
How much does a house cost in Seneca?
The median owner-occupied home in Seneca is valued at $227,500 (Census ACS 2020–2024), against a median household income of $86,830, so homes cost about 2.6 times income. Median rent is $1,149 a month.
What is the weather like in Seneca?
July highs average 84.0°F and January lows 14.2°F (NOAA 1991–2020 normals). It gets about 39.0 inches of precipitation a year and 25.0 inches of snow.
Does Seneca get tornadoes?
14 tornadoes have passed within 10 miles of Seneca since 1950 (NOAA Storm Events); the strongest was an EF3 on February 28, 2017. The typical Illinois town has had 27.
- U.S. Census Bureau, American Community Survey 5-year estimates (2020–2024)
- U.S. Census Bureau, 2020 Census and 2025 Gazetteer (2020 / 2025)
- NOAA NCEI U.S. Climate Normals (1991–2020)
- NOAA NCEI Storm Events Database (1950–2026)
- FEMA OpenFEMA Disaster Declarations (this product uses the FEMA OpenFEMA API but is not endorsed by FEMA) (1953–2026)
- NCES Common Core of Data (2023–24)
- BLS Quarterly Census of Employment and Wages; USDA ERS county unemployment (BLS LAUS) (2000–2024)
- The Town Files lifestyle rankings, built from federal demographic, school, crime and housing data (2025)