Archive for USPS

A new twist on ZIP Codes

pdZIP receives a major overhaul this month and includes new 5-digit ZIP Code and ZIP+4 databases, along with an alternate places reference file and some new twists on the concept of ZIP Code databases. It is available in Pro and Standard editions from our website.

There are more than 41,000 United States Postal Service (USPS) 5-digit ZIP Codes, and more than 46 million USPS ZIP+4 records, in the 50 U.S. states, the District of Columbia, military posts, and island areas. pdZIP provides core USPS information about them, along with time zones, area codes, GeoCoding data, and a host of useful demographic variables.

These easy-to-use, comprehensive, and up-to-date packages are designed for those who want to create custom databases or applications, stylize the address information on their mailings, or go beyond what is available from USPS address cleaning services.

Pro and Standard versions

Both the Pro and Standard editions include a 41,000 record 5-digit ZIP Code database along with an alternate places reference file. The Pro version adds 46 million ZIP+4 records. The Standard edition has everything except the ZIP+4 information.

  • (Pro, Standard) More than 41,000 5-digit ZIP Code records
  • (Pro only) More than 46 million ZIP+4 records
  • (Pro, Standard) Alternate places reference file listing preferred place names and acceptable and unacceptable alternate place names for USPS ZIP Codes
  • (Pro, Standard) Comprehensive United States national databases:
    • The 50 U.S. states
    • District of Columbia (federal district)
    • Overseas military areas
      • U.S. Armed Forces Americas (except Canada)
      • U.S. Armed Forces Europe (which serves Europe, Canada, Africa, and the Middle East)
      • U.S. Armed Forces Pacific (which serves Asia and the Pacific)
    • Insular areas:
      • American Samoa
      • Commonwealth of the Northern Mariana Islands
      • Commonwealth of Puerto Rico
      • Guam
      • Midway Islands (also known as Midway Atoll; now inhabited only by caretakers)
      • U.S. Virgin Islands
      • Wake Island (also known as Wake Atoll; now inhabited only by civilian contractors)
    • Associated island areas:
      • Republic of the Marshall Islands
      • Federated States of Micronesia
      • Republic of Palau
  • (Pro, Standard) Core USPS ZIP5 information:
    • USPS 5-digit ZIP Code
    • State postal abbreviation
    • USPS preferred city name
    • Formatted city name
    • Abbreviated city name
    • ZIP Classification Code
    • City-Delivery Carrier Routes Indicator
    • Bulk Mail Sort/Merge Indicator
    • Finance Number
  • (Pro only) Core USPS ZIP4 information:
    • USPS Plus4 Add-on Code
    • Carrier Route
    • Delivery Type Indicator
    • Street alias type and date
    • Alternate Record Indicator
    • Locatable Address Conversion System (LACS) Indicator
    • Move Indicator
    • Company or organization information
    • Puerto Rican urbanization
  • (Pro, Standard) Time Zones, UTC Offsets and Daylight Savings Time
  • (Pro, Standard) Area Codes
  • (Pro, Standard) ZIP5 GeoCoding is at both the Zip Code Tabulation Area (ZCTA) level and county level
  • (Pro only) ZIP+4 GeoCoding is at the census block group level or smaller
  • (Pro, Standard) Latitude and Longitude coordinates in 3 formats:
    • Degrees
    • Converted to radians (15 numeric places)—for trigonometry functions
    • Degrees/Minutes/Seconds— for printing out coordinates in documents and on websites
  • (Pro, Standard) Land and water area
  • (Pro, Standard) Urban and rural indicator
  • (Pro, Standard) Geographic areas identified:
    • Region
    • Division
    • State (FIPS Code and Name)
    • County (FIPS Code and Name)
  • (Pro only) Geographic areas identified:
    • Census Tract
    • Census Block Croup
    • Place (FIPS Code)
    • Congressional District (FIPS Code)
    • Census Zip Code Tabulation Area (ZCTA)
  • (Pro, Standard) Demographics (tabulations and estimates):
    • Population
      • Males
      • Females
      • Median age: Both genders
        • Median age: Males
        • Median age: Females
      • White
      • Black or African American
      • American Indian or Alaska Native
      • Asian
      • Native Hawaiian or other Pacific Islander
      • Other race
      • Two or more races
      • Hispanic or Latino
      • Speaks Spanish at home (age 5 and over)
      • Enrolled in PK-12 (age 3 and over)
      • Enrolled in college
      • Veterans (age 18 and over)
      • Military quarters population
      • College/University student housing population
      • Nursing/Skilled-nursing facility population
      • Adult correctional facilities population
      • Juvenile facilities population
      • Per capita income
      • Unemployed civilian population (age 16 and over)
    • Households
      • Average household size
      • Median household income
      • Households with income below the poverty level (in the past 12 months )
      • Family households
        • Average family size
        • Median family income
      • Non-family households
        • Median non-family income
    • Housing units
      • Median number of rooms
      • Median year built
      • Occupied housing units
        • Householder who is White
        • Householder who is Black or African American
        • Householder who is American Indian or Alaska Native
        • Householder who is Asian
        • Householder who is Native Hawaiian or other Pacific Islander
        • Householder who is another race
        • Householder who is two or more races
        • Hispanic or Latino householder
        • Average number of vehicles
        • Owner-occupied housing units
          • Median home value
        • Renter-occupied housing units
          • Median gross rent as a percentage of income
          • Median gross rent
            • Median contract rent
      • Vacant housing units
  • (Pro, Standard) Comes in multiple file formats:
    • Comma Delimited (CSV)
    • Fixed Length
    • DBF
  • (Pro, Standard) Full documentation
  • (Pro, Standard) Perpetual Site License—allowing installation on all computers in the same building within a single company or organization
  • (Pro, Standard) Available for immediate download

pdZIP utilizes only the ANSI character set (ASCII values 0 to 127 and extended values 128 to 255) and United States Postal Service (USPS) and U.S. Census Bureau coding conventions. These databases are fully compatible with raw USPS data and other databases and applications that make use of their coding conventions.

Product information


With respect to database management, one of the questions we are most often asked concerns the difference between CASS and DSF2 address/mail processing. These services have grown more similar in recent years, but there are still important differences.


CASS – Coding Accuracy Support System – standardizes addresses and improves the accuracy of carrier route, five-digit ZIP, ZIP+4 and delivery point codes that appear on mail pieces. When mailers CASS certify their lists, they can become eligible for bulk mail discounts from the U.S. Postal Service (USPS).

In the past, applying these codes only required that mailing address fall within a valid address range. The address itself was not necessarily accurate. For example, ZIP+4 codes typically represent a range of 100 or fewer house numbers on a given street. While 100-199 Rollins Road may be assigned to ZIP+4 code 91311-7007, not all those house numbers are actual delivery points.

Since November 2, 2006, the USPS has determined that CASS-related discounts will only apply when the agency’s Delivery Point Validation (DPV) process confirms the primary number—or the first line—of the addresses. If the primary street number of an address cannot be confirmed with DPV, then no ZIP+4 code is assigned to the mail. Without a ZIP+4 code, the mail ceases to qualify for postal discounts. DPV is therefore now included with CASS processing.

CASS also integrates Locatable Address Conversion System service (LACSLink) which converts some PO Box and rural route addresses to city-style addresses and updates addresses that have been renumbered or renamed.

CASS processing software is graded by the USPS National Customer Support Center (NCSC), located in Memphis, Tennessee, by processing a test file. To be certified a 98.5% accuracy rate is required.


Prior to the November 2006 requirements added to CASS processing, DSF2 – Delivery Sequence File Second Generation – was the only fail-safe method of checking the accuracy of mailing addresses since CASS only determined if the address fell within a valid address range. But DSF2 continues to offer advantages that can make it a good choice.

In addition to all the processing and validation supplied with CASS, DSF2 also provides mailers with other important address attributes. It classifies an address as residential or business, identifies the delivery type—curb-side, door-slot, Neighborhood Delivery and Collection Box Unit (NDCBU) or central delivery—and flags seasonal and vacant addresses.

This information allows for more targeted mailings. For example, a company may want to send out a sample box of laundry detergent—with DSF2 they can target their mailing to residential addresses that do not have a door-slot mailbox since the sample would not fit through the slot.

DSF2 also appends codes that can be used to qualify for USPS Enhanced Carrier Route (ECR) Basic, High Density and Saturation postal discounts. These include Pseudo Delivery Sequence Numbers for walk sequence postal presort discounts and Enhanced Line of Travel codes (eLOT).

CASS and DSF2 have similarities and important differences. The choice is determined by the targeting required and the postal discounts that can be qualify for. In both cases, however, users will typically benefit from a significant reduction in undeliverable mail, speedier delivery and lower costs.