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County ZIP codes · Iowa · FIPS 19089

Howard County, IA ZIP Codes

Howard County, Iowa has 9 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 6 of the residential ones lie mainly in Howard County and 3 mainly in a neighboring county; 6 cross the county line. Median household income ranges from $56,728 in 50466 (Riceville) to $100,559 in 52132 (Calmar) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Howard County?

50466 · Riceville: $57k50603 · Alta Vista: $74k50628 · Elma: $69k52132 · Calmar: $101k52134 · Chester: $63k52136 · Cresco: $71k52154 · Lawler: $58k52155 · Lime Springs: $58k52163 · Protivin: $78k521365046650628521555213252154506035213450466 · Riceville: $57k50603 · Alta Vista: $74k50628 · Elma: $69k52132 · Calmar: $101k52134 · Chester: $63k52136 · Cresco: $71k52154 · Lawler: $58k52155 · Lime Springs: $58k52163 · Protivin: $78k521365046650628521555213252154506035213450466 · Riceville: $57k50603 · Alta Vista: $74k50628 · Elma: $69k52132 · Calmar: $101k52134 · Chester: $63k52136 · Cresco: $71k52154 · Lawler: $58k52155 · Lime Springs: $58k52163 · Protivin: $78k5213650466506285215552132521545060352134
The residential ZIP codes of Howard 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?

They carry 9 postal town names.

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

All 9 residential ZIP codes in Howard County

6 ZIP codes lie mainly in Howard County; 3 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Howard County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
52136 Cresco 5,840 28 $71k $161k 67%
50466 Riceville 1,972 14 $57k $210k 60%
50628 Elma 1,423 13 $69k $154k 93%
52155 Lime Springs 1,110 11 $58k $117k 100%
52163 Protivin 333 188 $78k $115k 100%
52134 Chester 223 8 $63k $208k 100%

Partly in Howard County

Residential ZIP codes mainly in another county that reach at least 1% into Howard County, by their share here
In this county
50603 Alta Vista 555 12 $74k $123k 17%
52132 Calmar 1,759 28 $101k $232k 2%
52154 Lawler 592 8 $58k $156k 1%

Download the 9 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?

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

Share of each ZIP code's land in Howard County and in the neighboring counties
ZIPIn HowardElsewhere
5213667%Winneshiek County 33%
5046660%Mitchell County 40%
521322%Winneshiek County 98%
5062893%Mitchell County 7%
521541%Chickasaw County 99%
5060317%Chickasaw County 83%

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

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

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Howard County's ZIP codes use 3 prefixes: 504, 506 and 521.

Three-digit prefixes of Howard 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 Howard County's
PrefixSectional centerHereAll codes
504 Waterloo, IA (SCF 506) 1 57
506 Waterloo, IA (SCF 506) 2 70
521 Waterloo, IA (SCF 506) 6 33

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