Which ZIP code in St. Charles County has the lowest median age?

63301 (Saint Charles), at 38.0 (±1.0), among 11 ZIP codes with at least 1,000 residents.

Why are some ZIP codes missing?

ZIP codes with fewer than 1,000 residents are left out because their survey estimates swing too much to rank, and so are ZIP codes where the Census Bureau did not publish this figure.

Youngest ZIP codes in St. Charles County, MO

These are the 11 ZIP codes in St. Charles County with the lowest median age, out of 11 with at least 1,000 residents. 63301 (Saint Charles, 38.0), 63385 (Wentzville, 38.0) and 63368 (O Fallon, 38.0) lead the list. There is no single "best" ZIP code in St. Charles County; the right one depends on who you want to reach, so the same ZIP codes are ranked several ways below.

Youngest ZIP codes in St. Charles County

Rank	ZIP	Mailing city	Median age	Residents	Households	Residential mailboxes
1	63301	Saint Charles	38.0 ±1.0	52,667	21,462	23,411
2	63385	Wentzville	38.0 ±1.4	51,330	18,106	21,803
3	63368	O Fallon	38.0 ±1.1	46,966	17,271	18,325
4	63367	Lake Saint Louis	39.5 ±0.8	29,725	11,125	12,642
5	63366	O Fallon	40.4 ±1.3	54,769	20,967	21,505
6	63304	Saint Charles	40.7 ±1.1	43,195	16,284	17,988
7	63376	Saint Peters	40.9 ±0.8	74,962	30,034	31,724
8	63303	Saint Charles	41.4 ±1.3	46,089	20,690	21,072
9	63332	Augusta	41.6 ±6.7	1,651	616	625
10	63348	Foristell	43.0 ±2.1	10,394	3,781	3,253
11	63341	Defiance	48.6 ±2.6	3,515	1,324	1,558

How we ranked them

Ranked by median age of all residents, lowest first (ACS 5-year estimates, 2020–2024). ZIP codes need at least 1,000 residents to be ranked; 11 of 14 qualify.

Which of these to mail, and why

Younger ZIP codes skew toward renters, students and young families: fitness, quick-service food, apartments, entertainment and first-time-buyer offers.

The top five ZIP codes on this list hold 88,931 households, on 152 carrier routes with 97,686 residential mailboxes. Open any of them on the route map to see each carrier route's own figures before you choose.

Open 63301 on the EDDM route map

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Frequently asked questions

Which ZIP code in St. Charles County has the lowest median age?: 63301 (Saint Charles), at 38.0 (±1.0), among 11 ZIP codes with at least 1,000 residents.
How is this ranking calculated?: Ranked by median age of all residents, lowest first (ACS 5-year estimates, 2020–2024).
Why are some ZIP codes missing?: ZIP codes with fewer than 1,000 residents are left out because their survey estimates swing too much to rank, and so are ZIP codes where the Census Bureau did not publish this figure.

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.