Saint Charles County

Saint Charles County, Missouri — key demographics

Population

• Total population: 416,000 (2023 Census estimate); 405,262 (2020 Census)
• Growth: +2.7% since 2020; +12.4% since 2010

Age

• Median age: ~39 years (ACS 2023)
• Under 18: ~24%
• 65 and over: ~16%

Gender

• Female: ~50.7%
• Male: ~49.3% (ACS 2023)

Race/ethnicity (ACS 2023; shares of total population)

• White (non-Hispanic): ~84%
• Black or African American: ~5%
• Asian: ~4%
• Two or more races: ~4%
• Hispanic or Latino (any race): ~4–5%

Households and housing

• Households: ~154,000 (ACS 2023)
• Average household size: ~2.6–2.7
• Family households: ~70%; married-couple households: ~59%
• Owner-occupied housing rate: ~79–80%
• Median household income: about $100,000 (ACS 2023)

Source: U.S. Census Bureau (2023 Population Estimates; 2023 American Community Survey 1-year; 2020 Decennial Census). Margins of error apply to ACS estimates.

Saint Charles County (pop ~415,000; density ~730/sq mi) has high digital connectivity: 96% of households have a computer and 92% subscribe to home broadband; 4G/5G mobile broadband covers virtually all populated areas and fixed 25 Mbps+ service is available to >95% of residents. Gigabit cable/fiber is common in cities like O’Fallon, St. Peters, and St. Charles.

Estimated email users: ~310,000 residents (about 75% of the total population and ~92% of adults).

Age distribution of email users: 13–17: 5%; 18–34: 27%; 35–54: 38%; 55–64: 16%; 65+: 14%. Prime working-age cohorts are heavy users due to employment; 65+ adoption is rising with telehealth and banking.

Gender split: ≈51% women, 49% men among users; usage intensity comparable.

Digital access trends: Home broadband and smartphone adoption continue to increase; smartphone-only internet households ~9%; remote work ~13% of workers, driving higher email volume throughout weekdays.

Mobile phone usage in Saint Charles County, Missouri (2024 snapshot)

User base and adoption

• Population and adult base: ~416,000 residents (2023 Census estimate), ~320,000 adults. Estimated smartphone users: 290,000–300,000 adults.
• Household device and subscription profile (ACS 2018–2022 5‑year S2801):
  • Households with a smartphone: ~93–95% in Saint Charles County vs ~90–92% statewide.
  • Households with a cellular data plan: ~87–90% county vs ~82–85% Missouri.
  • Mobile-only internet (cellular data plan but no fixed home broadband): ~10–13% county vs ~18–22% Missouri.
• 5G device penetration: estimated 70–80% of active smartphones in the county, modestly above statewide levels (roughly mid‑60s to low‑70s) given higher incomes and newer device refresh cycles.

Demographic breakdown of usage

• Age: Strong usage among family and working‑age cohorts. County median age ~39; teen and young‑adult device penetration approaches saturation, with high multi‑device households (parents + children).
• Income and education: Median household income around the mid‑$90Ks (ACS), well above the Missouri median (~$65–70K). Higher income and higher bachelor’s‑degree attainment correlate with:
  • More postpaid, multi‑line family plans.
  • Higher 5G handset share and accessory ecosystem (watches, tablets).
  • Lower reliance on mobile‑only internet than Missouri overall.
• Race/ethnicity: A majority‑White, suburban county with growing Asian and Hispanic populations; these growth segments show high smartphone reliance but, in this county, still complement mobile with fixed broadband more than the state average.
• Work patterns: Large commuter and hybrid‑work base exhibits high daytime data demand along corridors (I‑70, MO‑364/Page, MO‑370) and in office/retail clusters (St. Peters, O’Fallon, Dardenne Prairie, Wentzville).

Digital infrastructure and performance

• Coverage: All three national carriers (AT&T, T‑Mobile, Verizon) provide countywide LTE and broad 5G low‑band coverage; mid‑band 5G capacity (n41/n77) is widely deployed in the populated south‑central/eastern half and along I‑70/364/370. Rural fringes northwest of Wentzville see more signal variability than the suburban core, but coverage gaps are fewer than typical Missouri counties.
• Capacity and speeds: Denser mid‑band 5G in the St. Louis metro (which includes Saint Charles County) yields higher median mobile download speeds than the Missouri statewide median. Peak‑hour slowdowns occur on commuter corridors and around large venues, but the county benefits from ongoing small‑cell densification tied to fiber backhaul.
• Backhaul and carriers of backhaul: Charter Spectrum and AT&T supply most metro fiber; Zayo and other metro‑fiber providers support enterprise/small‑cell backhaul. This fiber depth enables denser 5G and better consistency than in many non‑metro Missouri counties.
• Fixed‑mobile convergence: Because fixed broadband availability is strong (cable DOCSIS and growing AT&T Fiber), households often pair mobile with wireline; fixed‑wireless access (FWA) adoption exists but is a smaller share than in rural Missouri where fiber/coax options are limited.

Trends that differ from Missouri overall

• Higher adoption: Smartphone and cellular‑plan penetration in Saint Charles County is a few points higher than the state average, producing an adult smartphone user base near 300k.
• Lower mobile‑only reliance: Mobile‑only households are notably lower (about half the rural‑county rate), reflecting strong cable/fiber availability and higher incomes.
• Newer device mix: Faster 5G handset turnover and accessory adoption lead to higher per‑user data consumption and better realized 5G speeds than the statewide norm.
• Plan structure: More postpaid, multi‑line family plans; lower prepaid share than the state average, resulting in lower churn and higher ARPU.
• Network quality: Denser cell sites and fiber backhaul deliver stronger mid‑band 5G availability and higher sustained speeds than typical Missouri counties; coverage issues are more constrained to outer exurban pockets rather than broad rural zones.

Key takeaways

• Approximately 290k–300k adults in Saint Charles County use smartphones, with near‑universal adoption in family households and strong 5G presence.
• The county’s suburban, higher‑income profile reduces mobile‑only dependence and lifts device quality, speeds, and plan value relative to Missouri overall.
• Infrastructure depth—multi‑carrier 5G plus abundant fiber backhaul—positions the county ahead of statewide averages on capacity and performance, with congestion primarily a peak‑corridor and event‑driven issue rather than a coverage problem.

Saint Charles County, MO social media snapshot (2024, modeled from latest Pew Research Center U.S. usage rates applied to Saint Charles County demographics from the U.S. Census Bureau/ACS 2023)

Overall penetration

• Adults using at least one social platform: ~72% of adults

Most-used platforms among adults (share of adults who use each platform)

• YouTube: 83%
• Facebook: 68%
• Instagram: 50%
• TikTok: 33%
• Pinterest: 35%
• Snapchat: 30%
• LinkedIn: 30%
• WhatsApp: 24%
• X (Twitter): 22%
• Reddit: 22%
• Nextdoor: 19%

Age profile (share of each age group that uses any social media)

• 18–29: ~90%
• 30–49: ~82%
• 50–64: ~69%
• 65+: ~45%

Gender breakdown (share of total social media users in the county)

• Female: ~53–55%
• Male: ~45–47% Note: Women over-index on Facebook and Pinterest; men over-index on Reddit and X. Gender splits on YouTube, Instagram, and TikTok are close to even.

Behavioral trends observed in suburban Midwest counties like Saint Charles (consistent with platform usage patterns)

• Facebook is the local hub: heavy use of Groups (schools, youth sports, neighborhoods), Marketplace, and city/county updates. Strong daily check-in behavior; comments and shares outpace original posting for 30+.
• YouTube is universal utility: how-tos, home improvement, product research, and local civic content; high watch time on connected TVs in evening prime hours.
• Instagram is lifestyle and local business discovery: Stories/Reels drive awareness for restaurants, fitness, salons, boutiques; 18–34 skews heavier, with micro-influencer engagement.
• TikTok is fast-growing for food, events, and “things to do” discovery; strongest under 35, but algorithmic reach exposes local content beyond follower bases.
• Snapchat is entrenched among teens and college-age residents for messaging and quick updates; limited reach for broad marketing outside that cohort.
• LinkedIn is used by commuting professionals for networking and employer branding; effective for recruiting and B2B in the St. Louis metro labor shed.
• Nextdoor complements Facebook for hyperlocal issues (HOA, public safety, city services) with high homeowner engagement.
• Messaging layers matter: Facebook Messenger and Instagram DMs are primary customer-service channels for local SMBs; WhatsApp usage present but secondary compared with Messenger in this market.
• Time-of-day peaks: weekday 7–9 a.m. (commute/coffee), 11:30 a.m.–1 p.m. (lunch), and 7–10 p.m. (CTV co-viewing + mobile second-screening). Weekends see morning spikes for local plans and Marketplace.

Notes on method

• Percentages reflect Pew Research Center’s 2024 U.S. adult platform usage rates; county-level figures are modeled by applying those rates to Saint Charles County’s age/sex structure (ACS 2023). Use them as locality-calibrated estimates for planning.