How to Find Your UPRN Number
The National Land and Property Gazetteer and Local Land and Property Gazetteers are the backbone of UK address data infrastructure. Here is everything local authority teams need to know — and how UPRN matching keeps your data aligned with the national standard.
What is the LLPG — Local Land and Property Gazetteer?
A Local Land and Property Gazetteer (LLPG) is a definitive, council-maintained database of every addressable property and land parcel within a local authority's boundary. Each record in an LLPG contains a Unique Property Reference Number (UPRN), the full address in a standardised format, geographic coordinates, and classification information.
LLPGs are maintained by Local Land and Property Gazetteer Custodians — council officers responsible for keeping address records current and accurate. When a new property is built, an address is changed, or a building is demolished, the LLPG custodian updates the record and the change flows upstream into the national dataset.
Every local authority in England and Wales maintains its own LLPG. These local datasets are the source of truth for address data within each council area — and the foundation of the national dataset.
What is the NLPG — National Land and Property Gazetteer?
The National Land and Property Gazetteer (NLPG) is the aggregated national dataset built from contributions by all local authority LLPGs across England and Wales. It brings together every address and land parcel record into a single, nationally consistent dataset — forming the authoritative reference for UK property data.
The NLPG is managed by GeoPlace, the joint venture between the Local Government Association and Ordnance Survey. GeoPlace assigns UPRNs, maintains the data standards that govern how addresses are captured and formatted, and publishes the data as part of the AddressBase product suite used across central government, emergency services, and commercial organisations.
LLPG
→ Maintained by individual councils
→ Covers one local authority area
→ Updated by LLPG Custodian
→ Source data for the national dataset
→ Used internally across council services
LLPG vs NLPG — Key Differences
NLPG
→ Maintained by GeoPlace
→ Covers all of England and Wales
→ Updated via LLPG contributions
→ Published as AddressBase
→ Used by government, emergency services, commercial orgs
Gazetteer Management: Keeping Your LLPG Accurate
Effective gazetteer management is one of the most important — and most underresourced — functions in local authority data teams. An LLPG that falls behind creates ripple effects across every council service that depends on address data: housing allocations, revenues and benefits, environmental services, social care, and emergency response.
The core challenge is matching address data across systems:
Data entered inconsistently
Different services capture addresses differently — housing might use "Flat 2a" while revenues records "2A Flat". Neither matches the LLPG record.
Legacy system migrations
When council systems are upgraded or replaced, historical address data often arrives in non-standard formats that don't align with current LLPG records.
New developments
New-build properties are often occupied before their UPRN is formally assigned — creating a window where address records exist but can't be matched.
Address changes
Street renamings, property renumberings, and sub-divisions create address changes that need to be reflected across all systems simultaneously.
How UPRN Matching Supports LLPG Compliance
Semilariti's UPRN matching platform helps local authority teams keep operational data aligned with their LLPG by resolving address records from any council system back to their authoritative UPRN.
Whether you are cleaning a housing register, standardising a revenues dataset, or aligning social care records ahead of a system migration, Semilariti processes your address data and returns UPRN-matched, standardised records — ready to load back into your systems.
95% Accuracy
Industry-leading match rate on real-world council address data — including legacy records and non-standard entries.
Bulk Processing
Process an entire housing register or council tax database in a single upload. Results returned in 5 to 30 minutes.
Confidence Scores
Every matched record includes a confidence score — so your team knows exactly which records to trust and which need review.