ARDECO Local Population Time-Series – 1961-2024

The ARDECO Local Population Time-Series dataset provides total resident population counts at the level of Local Administrative Units (LAU) version 2021 (usually equivalent to municipality boundaries), fully consistent with the ARDECO database 1st of January population totals (2026.02 release), covering the period 1961–2024, with ten-year intervals between 1961 and 2021.

UNIT OF MEASURE: Total resident population.

RESOLUTION: Local Administrative Unit level.

COMPLETENESS: 100%.

POLICY CONTEXT: This dataset supports regional, urban and rural analyses by providing a harmonised LAU-level population time series consistent with ARDECO, enabling the assessment of long-term demographic change, population dynamics, growing and declining areas, and the assessment of the evolution of the degree of urbanisation in Europe.

METHODOLOGY: The ARDECO Local Population Time-Series – 1961-2024 was produced by reallocating population data from a set of heterogeneous spatial units to a single, target geography: Local Administrative Units (LAU) version 2021. This process was done using an dasymetric spatial interpolation, as follows: for each year in the time-series, the original spatial units were intersected with the target LAU 2021 boundaries, generating a set of intersected zones. The population counts of each year were then redistributed to each intersected zone proportionally to a residential built-up volume proxy and subsequently aggregated to the target LAU 2021 units. Residential built-up volume proxy for each year in the time-series was obtained from the GHSL built-up volume time series (GHS-BUILT-V, R2023A), modified with a residential mask from the LUISA Base Map 2018, which was kept fixed and applied unchanged across the entire time-series. Finally, the resulting population figures at LAU 2021 were rescaled to ensure full consistency with ARDECO 1st of January population totals (2026.02 release) at the NUTS3 level for each year in the time-series (with the exception of UK, which is not included in ARDECO). Population data for 2021 in EU27 countries, Liechtenstein, Norway, Switzerland, and Iceland were already originally available for the LAU version 2021.

DATA SOURCES: Population data (EU27, Norway, Liechtenstein, Switzerland): Eurostat, 2024; CensusHub, 2011-2021; historical LAU population data, 1961–2001. Population data (United Kingdom): UK Census, 2021; historical LAU population data, 1961–2011. Population data (Iceland): Iceland Census, 2021; historical LAU population data, 1961–2011.Origin territorial units (EU27, Norway, Liechtenstein, Switzerland): LAU version 2024, 2024; GISCO_DB geometries, 2011; historical LAU geometries, 1961–2001. Origin territorial units (United Kingdom): Output Areas, 2021; historical LAU geometries, 1961–2011. Origin territorial units (Iceland): MSOAs, 2021; historical LAU geometries, 1961–2011. Proxy data: GHSL Built-up Volume (GHS-BUILT-V, R2023A); LUISA Base Map, 2018. Target population reference: ARDECO database, reference date: 18 February 2026. Target territorial units: Local Administrative Units (LAU), version 2021.

UNCERTAINTY AND LIMITATIONS: Missing values and inaccuracies may be present in the input population datasets (CensusHub, historical LAU population data, ARDECO). Additional uncertainty is introduced during the reallocation of population to the LAU version 2021 boundaries. The proxy layer used for redistribution inherits limitations from the original datasets, including land-use classification errors and omission and commission errors. Furthermore, the disaggregation method assumes a perfect correlation between residential population and residential built-up volume within each intersected zone.