Learn About
The Commemorative
Quarter for
Illinois

Summary for Seneca

About Seneca (Click for our profile page)

Located in: Primarily La Salle County (see below). A portion of Seneca extends into Grundy County.

Time Zone: Seneca lies in the Central Time Zone (CST/CDT)

Telephone Area Codes: 815 & 779<1>

ZIP Code: 61360<2>

Elevation: 510 feet [155.45 m] above sea level<3>

From the 2010 US Census (For more detail, see our Census Page for Seneca)

Population

Year	Population
2019 Est:<4>	2,241 (5.48% decrease since 2010)
2010:	2,371 (15.49% increase since 2000)
2000:	2,053

Total Area:<5> 7.06 sq. miles [18.3 km²] - of which 6.06% is water (0.43 sq. miles [1.1 km²])

Housing Units:<6> 927

GPS Coordinates (Latitude/Longitude)<7>

For the purpose of mapping and calculating distances, we have chosen the following reference point for Seneca:

Lat: 41.304500° (or 41°18'16" N)

Lon: -88.609400° (or -88°36'33" W)

USGS Topo Map: Seneca<8>

Federal GNIS/FIPS Codes for Seneca

GNIS ID: 2399784

FIPS State / Place Code: 17 / 68640

(For more about Federal Codes, see our Misc Page for Seneca)

About La Salle County

The village of Ottawa is the County Seat for La Salle County.

From the 2010 US Census (For more detail, see our Census Page for La Salle)

Population

Year	Population
2019 Est:	108,669 (4.53% decrease since 2010)
2010	113,823 (2.08% increase since 2000)
2000:	111,509

Total Area: 1,148 sq. miles [2,973.7 km²] - of which 1.13% is water (13.01 sq. miles [33.7 km²])

Housing Units: 49,978

Official Website: https://lasallecountyil.gov/

Federal GNIS/FIPS Codes for La Salle

GNIS ID: 422247

FIPS State / County Code: 17 / 099

(For more about Federal Codes, see our Misc Page for Seneca)

About Illinois

From the US Census

Population

Year	Population
2019 Est:	12,667,017 (1.28% decrease since 2010)
2010:	12,830,632 (3.31% increase since 2000)
2000:	12,419,293

Websites for State of Illinois

Official Website: https://www.illinois.gov/

Tourism: https://www.enjoyillinois.com/

Parks: https://dnr.illinois.gov/

Fishing: https://www.ifishillinois.org/

Hunting: https://dnr.illinois.gov/hunting.html

Federal GNIS/FIPS Codes for State of Illinois

GNIS ID: 1779784

FIPS State: 17

(For more about Federal Codes, see our Misc Page for Seneca)

Footnotes ...

<1>	When there's a risk of an area code running out of phone numbers, an 'Overlay Area Code' is created that has the same geographic boundaries as the existing area code. In this case, the 815 code has been Overlayed with the 779 area code. New phone numbers in the Seneca area will be assigned with one of these codes: 815 or 779. As a result, placing a call in the Seneca area will require 10-digit dialing (where you enter both the area code and then the phone number).
<2>	ZIP Codes have been created by the United States Postal Service (USPS) as a way of grouping addresses to make delivery more efficient. The boundaries of the ZIP Code can be changed, re-assigned, eliminated or overlapped with other ZIP Codes. So keep in mind that any given ZIP Code is only 'loosely' associated with a village (such as Seneca). When looking for a ZIP Code, whether Seneca or elsewhere, it's always best to check the website of the United States Postal Service (USPS).
<3>	The elevation is an estimate for the area around Seneca - it will be higher in some places and lower in others.
<4>	Every year, the US Census Bureau creates a population estimate for the preceeding year. Keep in mind that this value is an estimate and not an actual count. The most recent Census estimate is for the year 2019.
<5>	The area value has been supplied by the US Census Bureau and it can be different than the geographic boundaries of Seneca. The value given by the Census Bureau reflects their statistical (or sampling) requirements. For example, if there is a cluster of people living just outside of the community's official boundary, the Census-defined area might be expanded to include that group.
<6>	A Housing Unit is a broad term for those places where people live (whether occupied or temporarily vacant), such as a house, an apartment, a mobile home, or an area that is considered as a separate living quarter. Separate living quarters (consisting of one or more rooms) are considered to be those places where people live, sleep and eat separately from others and that have access to the outside (either directly or by a shared hallway).
<7>	Longitude & latitude values may not be the geographic center of Seneca, rather it may be a prominent intersection or the center of population, etc. It will vary depending on the source.
<8>	Name of the USGS 7.5 Minute topographic map which includes Seneca.