Reference · UK statistical geography

UK statistical geography boundary changes

Every recorded change to a UK statistical geography code — 3,816 predecessor-to-successor relationships across 14 years, from the ONS Code History Database. Each reorganisation is one table: old code, new code, and the Statutory Instrument that made the change.

Why this exists

A GSS code identifies an area as it was constituted at a point in time. When a boundary review or a council reorganisation lands, codes terminate and new ones begin — and any dataset keyed on the old code silently stops joining. ONS records all of this, inside a 36 MB Access database. Nobody publishes it as a table you can read, sort, or download per reorganisation.

3,816 relationships across 14 years

Reorganisation	Codes replaced	Codes created	Relationships	Instrument
2025 local authority district below threshold	3	3	5	Name Change
2024 westminster constituency	632	632	1,359	The Parliamentary Constituencies Order 2023
2024 combined authority below threshold	2	1	2	The North East Mayoral Combined Authority (Establishment and Functions) Order 2024
2023 local authority district	17	4	17	The Cumbria (Structural Changes) Order 2022
2021 local authority district below threshold	7	2	7	The Northamptonshire (Structural Changes) Order 2020
2021 combined authority below threshold	1	1	1	none recorded
2020 local authority district below threshold	4	1	4	The Buckinghamshire (Structural Changes) Order 2019
2019 local authority district	16	7	16	The Bournemouth, Dorset and Poole (Structural Changes) Order 2018
2019 county below threshold	1	1	1	none recorded
2018 local authority district below threshold	3	3	5	Name Change
2018 combined authority below threshold	1	2	2	The Newcastle upon Tyne, North Tyneside and Northumberland Combined Authority (Establishment and Functions) Order 2018
2016 combined authority below threshold	5	5	5	none recorded
2016 local authority district below threshold	3	3	3	none recorded
2015 local authority district below threshold	1	1	2	none recorded
2013 local authority district below threshold	5	5	7	The East Hertfordshire and Stevenage (Boundary Change) Order 2013
2013 westminster constituency below threshold	1	1	1	none recorded
2013 metropolitan county below threshold	1	1	1	The Gateshead and Northumberland (Boundary Change) Order 2013
2012 local authority district below threshold	2	2	2	The St Albans and Welwyn Hatfield (Boundary Change) Order 2012
2011 local authority district below threshold	2	2	4	The East Dunbartonshire Council Area and Glasgow City Council Area (Princes Gate and Greenacres by Robroyston) Boundaries Alteration Order 2010
2010 westminster constituency	587	591	1,230	The Parliamentary Constituencies and Assembly Electoral Regions (Wales) Order 2006
2010 local authority district below threshold	5	5	5	Name Change
2009 westminster constituency	628	628	628	The Parliamentary Constituencies and Assembly Electoral Regions (Wales) Order 2006
2009 local authority district	448	420	449	The Bedfordshire (Structural Changes) Order 2008
2009 county	41	35	41	none recorded
2009 region (england) below threshold	9	9	9	none recorded
2009 metropolitan county below threshold	1	6	6	none recorded
2009 country below threshold	4	4	4	none recorded

A reorganisation gets its own page at 10 or more relationships. Smaller ones are listed here in full rather than given a page with four rows on it.

Provenance

Source: Office for National Statistics, Code History Database (June 2026)
Retrieved: 7 September 2026
Licence: Open Government Licence v3.0
Method: /methodology/geography-vintages

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