51104 ZIP Code, Sioux City, IA
51104 is a ZIP code in Sioux City, Iowa in Woodbury County. It covers 7.5 square miles of land. The closest ZIP codes are 51103, 51105 and 51101. 23,197 people live here in 8,729 households, more than in 9 of every 10 Iowa ZIP codes. At about 3,103 people per square mile it has suburban density, and owners and renters are mixed (65% own). Median household income is $75,362, close to the Iowa median of $75,059.
Quick facts
- Mailing city: Sioux City, IA
- County: Woodbury County
- Land area: 7.5 sq mi
- Population: 23,197
- Median household income: $75,362
- Carrier routes: 15 (9,023 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 23,197 |
| Households | 8,729 |
| Median household income | $75,362 |
| Income per person | $36,752 |
| Median age | 37.5 |
| Homeowners | 64.5% |
| Median home value | $211,100 |
| Median rent | $998 |
| Bachelor's degree or higher | 28.9% |
| Average commute (minutes) | 18.5 |
| Households with kids under 18 | 33.5% |
| Moved in the past year | 8.7% |
| Below the poverty line | 10.4% |
| Broadband internet | 87.9% |
| Speak a non-English language at home | 19.6% |
Household income
| % of households | Value |
|---|---|
| <$10K | 5.5% |
| $10–15K | 1.1% |
| $15–25K | 6.5% |
| $25–35K | 6.1% |
| $35–50K | 12.1% |
| $50–75K | 18.7% |
| $75–100K | 13.0% |
| $100–150K | 18.2% |
| $150–200K | 13.7% |
| $200K+ | 5.2% |
Age
| % of all residents | Value |
|---|---|
| <10 | 13.2% |
| 10–19 | 13.1% |
| 20–24 | 8.4% |
| 25–34 | 13.0% |
| 35–44 | 14.5% |
| 45–54 | 10.2% |
| 55–64 | 11.8% |
| 65–74 | 9.3% |
| 75+ | 6.4% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 39.2% |
| Owned outright | 22.8% |
| Rented | 33.8% |
| Vacant | 4.2% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 71.6% |
| Townhome | 4.7% |
| 2–4 units | 5.0% |
| 5–19 units | 8.9% |
| 20+ units | 9.2% |
| Mobile / other | 0.6% |
Businesses in 51104
295 business establishments with 4,147 employees (ZIP Codes Business Patterns 2023).
- Health Care and Social Assistance: 83
- Other Services (except Public Administration): 32
- Accommodation and Food Services: 27
- Construction: 24
- Retail Trade: 24
- Finance and Insurance: 19
- Administrative and Support and Waste Management and Remediation Services: 19
- Real Estate and Rental and Leasing: 18
EDDM carrier routes
51104 has 15 USPS carrier routes with 9,023 residential and 255 business mailboxes. Open the EDDM route map.
Carrier routes in 51104
51104 has 15 USPS carrier routes (15 city (C)) with 9,023 residential and 255 business mailboxes. Routes range from 366 homes (C047) to 1,021 homes (C040); the median route has 578 homes. The Census counted 8,729 households in 51104 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 0 |
| 250–499 | 5 |
| 500–749 | 8 |
| 750–999 | 1 |
| 1,000–1,499 | 1 |
| 1,500+ | 0 |
Best routes in 51104 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route C047 — USPS business mailboxes 90, 366 homes
- Route C036 — USPS business mailboxes 41, 662 homes
- Route C040 — USPS business mailboxes 28, 1,021 homes
- Route C071 — USPS business mailboxes 23, 663 homes
- Route C079 — USPS business mailboxes 12, 578 homes
Select these 5 routes on the route map
Every carrier route in 51104
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| C001 | City | 711 | 7 | $86,834 | — | — | — |
| C004 | City | 431 | 3 | $62,028 | — | — | — |
| C009 | City | 678 | 8 | $136,484 | — | — | — |
| C020 | City | 382 | 9 | $50,911 | — | — | — |
| C021 | City | 857 | 6 | $102,751 | — | — | — |
| C036 | City | 662 | 41 | $50,911 | — | — | — |
| C040 | City | 1,021 | 28 | $75,649 | — | — | — |
| C047 | City | 366 | 90 | $80,233 | — | — | — |
| C049 | City | 494 | 7 | $105,619 | — | — | — |
| C058 | City | 723 | 10 | $75,649 | — | — | — |
| C071 | City | 663 | 23 | $83,677 | — | — | — |
| C073 | City | 505 | 5 | $80,233 | — | — | — |
| C077 | City | 389 | 5 | $89,488 | — | — | — |
| C079 | City | 578 | 12 | $50,911 | — | — | — |
| C084 | City | 563 | 1 | $89,488 | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 51104 on the EDDM route map.
How route demographics are estimated
Mailbox counts come from USPS; demographics are estimates
The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).
How a route gets its figures: the block-group length-share method
We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.
Margins of error
Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.
Different years
USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.
Why some routes show identical figures
Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.
Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
Nearby ZIP codes
- 51103 — Sioux City city, IA (2.6 mi)
- 51105 — Sioux City city, IA (2.6 mi)
- 51101 — Sioux City city, IA (2.9 mi)
- 51108 — Sioux City city, IA (3.4 mi)
- 57049 — North Sioux City city, SD (5.5 mi)
- 68776 — South Sioux City city, NE (5.6 mi)
- 51109 — Sioux City city, IA (6.2 mi)
- 51106 — Sioux City city, IA (6.7 mi)
Areas that include 51104
- Sioux City, IA ZIP codes — 8 ZIP codes
- Woodbury County ZIP codes — 26 ZIP codes
- Iowa ZIP code data
Where it ranks
- No. 5 of 16: highest share of households with children in Woodbury County
- No. 4 of 7: highest median household income in Sioux City, IA
- No. 1 of 6: highest median home value in Sioux City, IA
- No. 5 of 7: highest share of owner-occupied homes in Sioux City, IA
- No. 3 of 7: highest share of households with children in Sioux City, IA
- No. 4 of 7: highest share of residents who moved in during the past year in Sioux City, IA
- No. 4 of 7: lowest median age in Sioux City, IA
- No. 4 of 7: highest median age in Sioux City, IA
- No. 4 of 6: fastest population growth in Sioux City, IA
Mail every home in 51104
Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.
EDDM guides
ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 51104, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 51104 in?
- 51104 is a Sioux City, IA mailing address. By land area, 100% lies inside Sioux City.
- What county is 51104 in?
- 51104 is in Woodbury County.
- What is the population of 51104?
- About 23,197 people (±1,256), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 23,080.
- What is the median household income in 51104?
- $75,362 (±$7,177), compared with $75,059 for Iowa as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 51104?
- 15 USPS carrier routes with 9,023 residential and 255 business mailboxes (9,278 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 51104?
- The closest, measured center to center: 51103 (2.6 mi, Sioux City), 51105 (2.6 mi, Sioux City), 51101 (2.9 mi, Sioux City), 51108 (3.4 mi, Sioux City), 57049 (5.5 mi, North Sioux City) and 68776 (5.6 mi, South Sioux City).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.