Multi-County Zip Code Data (MCZ):

Zip Codes often cross county lines (sometimes 3 or more counties). The MCZ file contains a zip code, plus the possible counties in which the zip code may cross over. It also has an estimated percentage of the zip code that falls within that county.

This file is ideal for those applications where you need to know if a Zip Code is entirely in one county or not, such as:

• Tax calculations
• Insurance rate calculations
• HMO coverage area determination
• Sales territory assignments
• Fraud detection

This file is currently updated about every 2 to 3 months. The following fields are included in the data file:

• Zip Code
• A Sequence Number (for prioritizing the counties within a zip code [sequence 1 is the main county for the zip code])
• State Abbreviation
• City
• County
• State FIPS Code
• County fIPS Code
• Percentage of the total Zip Code that this county covers

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