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U.S. ZIP Codes Database 2026

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ZIP Code Details for Sioux City

Detailed geographic and postal record lookup for the city of Sioux City.

Postal Information

ZIP Code 51101
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable Wickham Spur
Time Zone America/Chicago
Area Codes 712
Latitude 42,5° N
Longitude -96,39° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51102
Type Po Box
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 712
Latitude 42,5° N
Longitude -96,39° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51103
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 402, 531, 712
Latitude 42,52° N
Longitude -96,44° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51104
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 712
Latitude 42,54° N
Longitude -96,4° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51105
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 712
Latitude 42,51° N
Longitude -96,35° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51106
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 402, 531, 712
Latitude 42,46° N
Longitude -96,32° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51108
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable James
Time Zone America/Chicago
Area Codes 712
Latitude 42,57° N
Longitude -96,35° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51109
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable Blvd Station
Time Zone America/Chicago
Area Codes 402, 531, 605, 712
Latitude 42,58° N
Longitude -96,47° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 51111
Type Standard
Primary City Sioux City
State IA
County Woodbury County
Acceptable Cities -
Unacceptable -
Time Zone America/Chicago
Area Codes 402, 531, 712
Latitude 42,42° N
Longitude -96,39° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of Sioux City, IA

Postal Information

ZIP Code 57049
Type Standard
Primary City North Sioux City
State SD
County Union County
Acceptable Cities Dakota Dunes, Mccook Lake, N Sioux City
Unacceptable -
Time Zone America/Chicago
Area Codes 402, 531, 605, 712
Latitude 42,53° N
Longitude -96,5° W

About U.S. ZIP Codes

U.S. ZIP Codes are 5-digit postal codes introduced in 1963 by the USPS to improve mail sorting efficiency. The first digit represents a broad region, the next two identify a sectional center facility, and the final two help pinpoint a local post office or delivery area.

Geographic Breakdown:

  • 1st Digit: Represents a group of states or a broad national region.
  • 2nd/3rd Digits: Represent a regional area or large city.
  • 4th/5th Digits: Identify specific post offices or delivery zones.

ZIP Codes support physical delivery, routing analytics, geocoding, tax calculations, and location-based research.

Geographic Map of North Sioux City, SD

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Postal context

About U.S. ZIP Codes

ZIP codes are a United States Postal Service system introduced in 1963 to make mail routing more accurate and efficient. The standard format uses five digits, while ZIP+4 adds four more digits for a more precise delivery segment.

ZIP codes cover the United States, its territories, military mail routes, and other USPS delivery points. This directory organizes that data for practical lookup by ZIP code, city, county, and state.