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Summary for Monmouth

About Monmouth (Click for our profile page)

Located in: Warren County (see below)

Pronunciation: MON-muhth <1>

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

Telephone Area Codes: 309 & 861<2>

ZIP Code: 61462<3>

Elevation: 730 feet [222.5 m] above sea level<4>

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

Population

Year	Population
2019 Est:<5>	8,870 (6.08% decrease since 2010)
2010:	9,444 (4.03% decrease since 2000)
2000:	9,841

Total Area:<6> 4.23 sq. miles [11 km²]

Housing Units:<7> 3,792

Official Website: www.ci.monmouth.il.us/

GPS Coordinates (Latitude/Longitude)<8>

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

Lat: 40.914000° (or 40°54'50" N)

Lon: -90.642000° (or -90°38'31" W)

USGS Topo Map: Monmouth<9>

Federal GNIS/FIPS Codes for Monmouth

GNIS ID: 2395371

FIPS State / Place Code: 17 / 50010

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

About Warren County

The city of Monmouth is the County Seat for Warren County.

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

Population

Year	Population
2019 Est:	16,844 (4.91% decrease since 2010)
2010	17,713 (5.46% decrease since 2000)
2000:	18,735

Total Area: 543 sq. miles [1,406.5 km²]

Housing Units: 7,682

Official Website: https://warrencountyil.gov/

Federal GNIS/FIPS Codes for Warren

GNIS ID: 1785134

FIPS State / County Code: 17 / 187

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

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 Monmouth)

Footnotes ...

<1>	The pronunciation we've provided is our attempt to give a phonetic pronunciation for Monmouth. While it might not be exactly right, hopefully it will be close. If we have it wrong or there's a better way to pronounce the name, please contact us through our Feedback Page.
<2>	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 309 code has been Overlayed with the 861 area code. New phone numbers in the Monmouth area will be assigned with one of these codes: 309 or 861. As a result, placing a call in the Monmouth area will require 10-digit dialing (where you enter both the area code and then the phone number).
<3>	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 city (such as Monmouth). When looking for a ZIP Code, whether Monmouth or elsewhere, it's always best to check the website of the United States Postal Service (USPS).
<4>	The elevation is an estimate for the area around Monmouth - it will be higher in some places and lower in others.
<5>	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.
<6>	The area value has been supplied by the US Census Bureau and it can be different than the geographic boundaries of Monmouth. 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.
<7>	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).
<8>	Longitude & latitude values may not be the geographic center of Monmouth, rather it may be a prominent intersection or the center of population, etc. It will vary depending on the source.
<9>	Name of the USGS 7.5 Minute topographic map which includes Monmouth.