Seneca, Illinois.
Typical home $254,944 (+5.0% in a year). Ottawa, IL metro.
to buy the typical home at today's mortgage rate — +$679 (+103%) since Jan 2020.
- 1 year
- Up $12,237 +5%
- $242,707$254,944 since Sep 2025
- 5 years
- Up $50,036 +24%
- $204,908$254,944 since Sep 2021
Monthly payment to buy the typical home
Home value × that month's 30-year mortgage rate, 20% down, principal and interest. This is the line households feel: prices and rates compound each other.
- Seneca$1,338
- Illinois$1,553
- United States$1,922
At the last five years' pace, a typical home here doubles in price every 16 years.
Typical home values in Seneca, IL rose 5.0% over the past year — faster than the nation's +1.2%.
Living in Seneca, LaSalle County, Illinois
Seneca is a village of 2,353 people in LaSalle County. Half its households earn more than $86,830 a year and half less, against $73,045 across LaSalle County. 81% of its homes are lived in by their owners and 19% are rented. Unemployment in LaSalle County was 4.4% in August 2026, and the county had 1.3% fewer jobs in 2025 than the year before. The most residents work in schools and health care, then transport and warehouses.
Written by AI Claude Sonnet 5.5 wrote this on 23 October 2026 from the figures here, a list of nearby places and what it knows. It can be wrong or out of date.
What it’s like
The place. Seneca is a small village where most homes are lived in by their owners, and household incomes run higher than across LaSalle County as a whole. Relatively few adults hold a four-year degree. Winters are cold, with January the coldest month, and the town sees a fair amount of snow each year, while July is the warmest month and brings warm days.
Work. Residents work mostly in schools, hospitals and social care, followed by transport, warehouses and utilities, and manufacturing. Across LaSalle County, some of the largest workplaces are Constellation, which generates nuclear power, OSF Saint Elizabeth Medical Center, and Ottawa Regional Hospital & Healthcare. Unemployment in the county is lower than it was a year earlier, though the county has fewer jobs than it did the year before, and getting to work typically takes a moderate stretch of time.
Things to do. A short drive away are Illini State Park and Gebhard Woods State Park, both protected areas, along with LaSalle Lake State Fish and Wildlife Area. Starved Rock State Park, one of the best known protected areas in the region, is a longer drive away, as is the Kankakee River for time on the water.
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- 907households
- 15%of adults have a degree
- 26 mintypical commute
- 8%work from home
What residents work in
Employed residents by industry, from the Census survey. LaSalle County had 38,720 jobs in 2025, 1.3% fewer than the year before (Bureau of Labor Statistics).
Weather through the year
Coldest in January, with highs near 31° and lows near 14°; warmest in July, with highs near 84° and lows near 62°. About 25 inches of snow and 39 inches of rain and melted snow a year.
Average daily high and low, 1991–2020, at the Marseilles Lock weather station, 7 miles away (NOAA).
Largest workplaces in LaSalle County
- ConstellationElectric power generation, nuclear684
- OSF Saint Elizabeth Medical Center SEMC614
- Ottawa Regional Hospital & HealthcarGeneral hospital561FTE
- James Hardie Building Products, PeruConcrete products, precast, manufacturing450
- PetSmart, Inc. 0036General warehousing and storage426
- WalmartWarehouse clubs and supercenters390
- Illinois Valley Community CollegeTwo-year college351
- WalmartWarehouse clubs and supercenters326
Staff on average in 2025, as each workplace reported it to OSHA with its injury records: 117 workplaces with 20 or more staff, 13,309 people in all across the county; Seneca has two of its own. Hospitals come from their Medicare cost reports (CMS, 2023) and colleges from IPEDS (NCES, 2023–24); FTE marks full-time equivalent staff. Not listed: many offices and banks, which need not report to OSHA; military bases, whose staff OPM withholds; and, in about half the states, city and county governments.
Natural hazards
- Cold wavesVery high
- Inland floodingVery high
- Strong windRelatively high
- TornadoesRelatively high
- DroughtRelatively moderate
- Winter weatherRelatively moderate
FEMA’s National Risk Index (December 2025) rates the risk each natural hazard poses to the people, buildings and farms in Seneca’s census tracts, against the rest of the country; all of them together, relatively high. It is meant for planning, not a substitute for a local risk assessment or a flood map: FEMA’s index.
From the U.S. Census Bureau’s 2020 census and its American Community Survey (2020–2024 five-year estimates), and the Bureau of Labor Statistics. A survey, so each figure has a margin of error, and figures it is not sure of are left out. More on LaSalle County and the Ottawa, IL metro.
Seneca home values
Zillow measures a city over its municipal boundary. Against the state and national figures, mid-tier homes, smoothed and seasonally adjusted.
- Seneca$254,944
- Illinois$295,943
- United States$366,157
When this market ran hot
Each cell is that month's year-on-year home-value growth. Read left to right, top row is the latest year — the 2021–22 band is the boom.
Market heat, inside the city limits
Homes for sale
Active for-sale inventory. More supply hands power to buyers.
- Seneca5
Zip codes with a Seneca address
A different geography, not a breakdown. The figure above covers the municipality; these zips cover everywhere the Post Office calls Seneca — often including townships beyond the city limits. Both come straight from Zillow, and they are not expected to average out.