Data Last Updated: July 1, 2025

Monroe County, IL ZIP Codes

ZIP Codes: Shows how many general ZIP Codes, PO Boxes, Unique (Business), and Multi County ZIP Codes are associated with Monroe, IL.	11 ZIP Codes (4 General, 3 PO Box, 0 Unique, & 4 Multi County) [More Details]
Area Codes: The Telephone Area Codes that are associated with Monroe, IL. Area Codes are used in the North American Numbering Plan (NANP) to facilitate phone routing. There are approximately 350 area codes in use in the United States.	618, 730
Timezone: Time zone designation within the U.S. Please note that not all areas in the U.S. observe daylight saving time which can affect actual local time for this city. There are 7 standard time zones which are, from west to east: Hawaii-Aleutian, Alaska, Pacific, Mountain, Central, Eastern, Atlantic. Also included in U.S. Territories are Samoa, Guam and Palau.	Central
Local Time: The current local time for each timezone. If more than 1 time zone for this area, all local times will be shown. Counties can cross timezones, so more than 1 may be shown.	12:00:00 AM
Population: The population of Monroe, IL from the U.S. Census 2020. Included are U.S. Citizens, permanent residents, temporary migrants, and undocumented individuals. The total population represents people who live in the city, not just those present while the Census was being completed.	34,962 [More Details]
FIPS: FIPS stands for Federal Information Processing Standards, which are a set of publicly announced standards for computer systems. A county FIPS code is a unique numeric identifier for a county in the United States, assigned by the National Institute of Standards and Technology (NIST). County FIPS codes have five digits, with the first two digits identifying the state and the last 3 indicating the county.	17133
CBSA: A Core Based Statistical Area (CBSA) is the recognized term for a region that functions around an urban core with a population of at least 10,000 people, according to the standards set by the Office of Management and Budget (OMB) in 2000. A CBSA is divided into two subsets: Metro and Micro, and these classifications are determined by population density. A Micro area is identified by a population ranging between 10,000 to 50,000, while a Metro area is defined as having a population that exceeds 50,000.	St. Louis, MO-IL
Land Area: The approximate amount of land area covered by Monroe, IL in square miles. The Land Area provided by the Census Bureau is based on geographic boundaries that include the mainland, islands, inland, coastal, Great Lakes, and territorial waters associated with each city.	385 square miles
Water Area: The approximate amount of water area covered by Monroe, IL in square miles. Calculations by the Census Bureau for Water Area take into account inland bodies of water, coastal regions, Great Lakes, and territorial sea waters. This encompasses features such as lakes, reservoirs, rivers, and coastal water bodies.	13 square miles
Coordinates: The latitude/longitude centroid coordinates for Monroe County, IL.	-90.177269, 38.278532
Quick Link: Copy the direct link to the Monroe, ILCounty page and use anywhere you like!	https://www.zip-codes.com/county/il-monroe.asp

Monroe, IL ZIP Code Boundaries

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Monroe County, IL Covers 11 ZIP Codes

ZIP Code	Classification	City	Population	% of Population
ZIP Code 62236	General	Columbia	13,924	39.83%
ZIP Code 62240 *	General	East Carondelet	1,645	--
ZIP Code 62244	General	Fults	1,059	3.03%
ZIP Code 62248	P.O. Box	Hecker	429	1.23%
ZIP Code 62256	P.O. Box	Maeystown	66	0.19%
ZIP Code 62264 *	General	New Athens	3,147	--
ZIP Code 62277 *	General	Prairie Du Rocher	1,113	--
ZIP Code 62278 *	General	Red Bud	6,646	--
ZIP Code 62279	P.O. Box	Renault	97	0.28%
ZIP Code 62295	General	Valmeyer	1,514	4.33%
ZIP Code 62298	General	Waterloo	17,630	50.43%

* Indicates a Multi County ZIP Code. These ZIP Codes partially cross over into Monroe, IL, but will mostly cover area in a different County. Not included in % of Population calculations.

Important Monroe, IL Information

Monroe County, IL Covers 11 ZIP Codes. This includes 4 General ZIP Codes, 3 PO Box ZIP Codes, and 0 Unique (reserved for Business and Volume Mail Receivers). There are also 4 Multi County ZIP Codes. These records are assigned a different primary county, but they partially cover area in Monroe County.

The population for Monroe County is 34,962, according to the U.S. Census. Population Density is 90.81 persons per square mile. With 14,540 Housing Units, the Average Household Size is 2.52 persons. There are 13,752 Family Households with an Average Family Size of 2.64 persons. 1.92% of the population is without Health Insurance. The 67.02% Employment Rate is 7.22% above the national average of 59.8%.24,896 people aged 25+ have some educational achievement, with 38.23% (or 9,518 people) having attained a Bachelor's Degree or higher.More Demographics are available below.

There are 2 area codes serving this area including618 and 730. Monroe is also located in the Central timezone and the current local time is shown above.

Monroe is part of the St. Louis, MO-IL Core Based Statistical Area (CBSA). Its CBSA Code is 41180.It is classified as a metro area, which means the combined population is 50,000 or more (at its core).

CBSAs are defined by the OMB as geographic areas that have at least one core with a population of 10,000 or more (for a micro area) and adjacent territory with a high degree of social and economic integration. CBSA codes are commonly used to accurately file Medicare claims and to verify applicable incentives using a patient's ZIP Code.

ZIP Codes in Monroe, IL have 14,101 Residential mailboxes and 738 Business mailboxes.There are 853 businesses with a total of 8,265 employees. That is an average of 9.7 employees per business. Annual payroll for these businesses is $366,090,000. Other Demographics

Monroe County Demographic Profile

Population & People

Total Population

34,962

Income

Median Household Income

$101,635

Housing

Total Housing Units

14,540

Health

Without Healthcare Coverage

1.92%

Business & Economy

Total Businesses

853

Families

Total Households

13,752

Employment

Employment Rate

67.02%

Education

Bachelor's Degree or Higher

38.23%

Total Population: Total number of people from the 2020 U.S. Census for Monroe, IL. This reflects the exact count of this area at that point in time, not future estimates, regardless of citizenship or immigration status. It is intended to count all persons living within the geographic area, not just those present on the day of the census.	34,962
Current Population Estimate: This field gives the estimated household population for All ZIP Codes in Monroe, IL. This is derived from known delivery information, household occupancy rates, household size, and more to come up with an accurate estimation for the current population. IMPORTANT: This does not include population totals for persons in nursing homes, correctional facilities, or other institutions. This is an estimation of the household population based on US Postal Service delivery information.	35,627
Total Households: Total number of Households from the 2020 U.S. Census for Monroe, IL. A Household includes everyone living in a residential housing unit. This includes families, roommates in a single residence, or a person living alone.	13,752
Total Housing Units: The total number of Housing Units is the number of occupied units + the number of vacant units. Ownership is defined by whether the unit is occupied by an owner or by a tenant. Owner occupancy means that the owner lives in the unit. This value comes from the 2020 U.S. Census and is not a projection or estimate.	14,540
Average Household Size: The Average Household Size, is obtained by dividing the number of people in Households (excluding those in group quarters, nursing home, prisons, and dorm rooms) by the number of Households. A Household includes everyone living in a residential unit. Those who do not live in a household are classified as living in group accommodation. This value is an estimate from the U.S. Census ACS (American Community Survey) and is updated yearly.	2.52
Average Family Size: Average Family Size is calculated by dividing the number of people in a Family Household by the number of Family Households. The U.S. Census Bureau defines family households as households consisting of two or more individuals who are related by birth, marriage, or adoption. They also may include other unrelated people. Non-family households consist of people who live alone or who share their residence with unrelated individuals. The Average Family Size only looks at the households classified as Family Households. This value is an estimate from the U.S. Census ACS (American Community Survey) and is updated yearly.	2.64

Other Monroe Demographics

# Residential Mailboxes: The number of active residential delivery mailboxes and centralized units. This excludes PO Boxes and all other contract box types.	14,101
# Business Mailboxes: The number of active business delivery mailboxes and centralized units. This excludes PO Boxes and all other contract box types.	738
Total Delivery Receptacles: The total number of delivery receptacles. This includes curb side mailboxes, centralized units, PO Boxes, NDCBU, and contract boxes. This count is for Residential and Business combined.	17,834
Single Family Delivery Units: Total count of single family mail delivery receptacles; generally analogous to homes.	12,533
Multi Family Delivery Units: Total count of multifamily mail delivery receptacles; generally analogous to apartments.	162

# of Businesses: The total number of Business Establishments. Data taken from Business Census 2023.	853
1st Quarter Payroll: The total payroll for the first quarter. Data taken from Business Census 2023.	$78,855,000
Annual Payroll: The total annual payroll . Data taken from Business Census 2023.	$366,090,000
# of Employees: The total number of employees for all ZIP Codes in this City. Data taken from Business Census 2023.	8,265

Sum of all ZIP Codes assigned Monroe, IL as their primary County.

References

U.S. Postal Service [Last Updated: 7/1/2025], https://www.usps.com
ZIP-Codes.com Internal Data Creation [Last Updated: 7/1/2025], https://www.zip-codes.com
U.S. Geological Survey [Updated as needed], https://www.usgs.gov
U.S. Census [Updated Yearly], https://www.census.gov
U.S. Census 2020 [Decennial] [Last Updated: 5/25/2023], https://www.census.gov