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County ZIP codes · Iowa · FIPS 19133

Monona County, IA ZIP Codes

Monona County, Iowa has 14 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 9 of the residential ones lie mainly in Monona County and 5 mainly in a neighboring county; 9 cross the county line. Median household income ranges from $61,599 in 51529 (Dunlap) to $80,750 in 51063 (Whiting) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Monona County?

51010 · Castana: $89k51026 · Hornick: $81k51034 · Mapleton: $66k51040 · Onawa: $71k51051 · Rodney: $52k51055 · Sloan: $72k51056 · Smithland: $103k51060 · Ute: $53k51063 · Whiting: $81k51523 · Blencoe: $83k51529 · Dunlap: $62k51545 · Little Sioux: $70k51558 · Moorhead: $77k51572 · Soldier: $70k515295102651034510405155851010510635105551060515455152351572510565105151010 · Castana: $89k51026 · Hornick: $81k51034 · Mapleton: $66k51040 · Onawa: $71k51051 · Rodney: $52k51055 · Sloan: $72k51056 · Smithland: $103k51060 · Ute: $53k51063 · Whiting: $81k51523 · Blencoe: $83k51529 · Dunlap: $62k51545 · Little Sioux: $70k51558 · Moorhead: $77k51572 · Soldier: $70k5152951026510345104051558510105106351055510605154551523515725105651010 · Castana: $89k51026 · Hornick: $81k51034 · Mapleton: $66k51040 · Onawa: $71k51051 · Rodney: $52k51055 · Sloan: $72k51056 · Smithland: $103k51060 · Ute: $53k51063 · Whiting: $81k51523 · Blencoe: $83k51529 · Dunlap: $62k51545 · Little Sioux: $70k51558 · Moorhead: $77k51572 · Soldier: $70k515295102651034510405155851010510635105551060515455152351572
The residential ZIP codes of Monona County (whole outlines, including the parts in neighboring counties), shaded by median household income in national fifths (ACS 2020-2024). <$54.1k$98.1k+no figure

Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).

How different are its ZIP codes?

The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $61,599 and $71,179.

They carry 14 postal town names.

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).

All 14 residential ZIP codes in Monona County

9 ZIP codes lie mainly in Monona County; 5 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Monona County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
51040 Onawa 3,500 27 $71k $152k 100%
51034 Mapleton 1,674 14 $66k $121k 80%
51063 Whiting 1,072 15 $81k $160k 100%
51060 Ute 706 12 $53k $99k 77%
51558 Moorhead 549 6 $77k $100k 91%
51010 Castana 425 6 $89k $115k 100%
51523 Blencoe 379 8 $83k $137k 92%
51572 Soldier 371 9 $70k $101k 100%
51051 Rodney 39 12 $52k $171k 100%

Partly in Monona County

Residential ZIP codes mainly in another county that reach at least 1% into Monona County, by their share here
In this county
51055 Sloan 1,346 21 $72k $218k 49%
51026 Hornick 910 8 $81k $211k 35%
51545 Little Sioux 267 6 $70k $80k 28%
51529 Dunlap 1,732 13 $62k $157k 18%
51056 Smithland 346 10 $103k $157k 15%

Download the 14 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).

Which ZIP codes cross the county line?

9 ZIP codes of Monona County extend into another county. A ZIP code follows mail routes, not county borders.

Share of each ZIP code's land in Monona County and in the neighboring counties
ZIPIn MononaElsewhere
5152918%Harrison County 38%; Crawford County 28%; Shelby County 15%
5103480%Woodbury County 16%; Crawford County 4%
5105549%Woodbury County 51%
5102635%Woodbury County 65%
5106077%Crawford County 23%
5155891%Harrison County 9%
5152392%Harrison County 8%
5105615%Woodbury County 85%
5154528%Harrison County 72%

Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).

Which first three digits do Monona County's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Monona County's ZIP codes use 2 prefixes: 510 and 515.

Three-digit prefixes of Monona County's ZIP codes, the sectional center for each (USPS labeling list L005, effective October 1, 2026) and how many of the prefix's codes are Monona County's
PrefixSectional centerHereAll codes
510 Sioux Falls, SD (SCF 570) 9 55
515 Omaha, NE (SCF 680) 5 57

Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.