This page explains how Zipcodes.ng sources and checks its postal code data, and what we do when a page turns out to be wrong.
Source
Every code on this site originates from NIPOST’s published postal code allocation. NIPOST does not publish a live, machine-readable database — the allocation exists as historical published lists, and every public Nigerian postcode directory we’ve checked, including this one, traces back to the same circa-2009 source lineage. We can’t call a code “verified” against an authoritative live system, because no such system is publicly available today.
What we check
- Internal consistency: does a page’s code match the prefix pattern used by every other LGA in its state? A mismatch is a strong signal of misfiled or duplicated data.
- Duplicate content: do two different LGA pages share the same street table? Real LGAs don’t share postal-code data, so an exact or near-exact match between two distinct places means one, or both, is wrong — not that the places are actually the same.
- Malformed entries: truncated codes, blank cells, and formatting errors get corrected only when the surrounding table makes the fix unambiguous — for example, when a 5-digit code can only complete to one specific 6-digit value already used elsewhere in the same table. We don’t guess at digits we can’t confirm from context.
What we do when something doesn’t check out
- If we can restore a page’s original data, from an earlier archived version for instance, we do.
- If two LGAs share the same data and we can’t tell which one it actually belongs to, we remove both pages from search results rather than guess. Showing possibly-wrong data to someone filling out a form is worse than showing nothing.
- If a page’s data is confirmed wrong for that LGA — another place’s data filed under the wrong name — we remove it from search results and try to source or restore the real thing later.
What “Last reviewed” means
A specific “Last reviewed” date on an LGA page means we’ve personally checked that page’s table for the issues above. A page without that date hasn’t been through this process yet — the code is still NIPOST’s published allocation, just not independently re-checked by us. We’d rather say “not yet checked” than imply certainty we don’t have.
Help us find errors
If you know an area and see a code that looks wrong, use the “Spotted a wrong code? Tell us” link on that page. Local knowledge is the fastest way we find data that needs fixing.