Historically, there are a small percentage of cases where a wrong geographic boundary or coding of a housing unit was used to produce the official census population and housing counts for a local area. Geocoding errors can occur when a living quarter such as a house, apartment, or military vessel, is placed in an incorrect location. There may also be processing errors.

The Census Bureau works with state, local, and tribal governments to help ensure a complete and accurate count during each census. Elected officials may challenge their jurisdiction’s census counts. During the challenge process, the Census Bureau will not collect any additional data. If a challenge results in a change, the bureau issues official revised counts to the affected government. All data, geography, and technical documentation notes and errata are published.