The OECD definition of functional urban areas (FUAs) capture meaningful connections between cities and their surrounding areas. The degree of urbanisation provides a definition of cities based on population density and cell contiguity. The FUA definition expands city boundaries to include areas economically connected through workplace commuting. The definition uses population density and travel-to-work flows as key information.
OECD Definition of Cities and Functional Urban Areas
Cities concentrate a considerable share of population and economic activity in OECD countries. Comparing cities across countries requires appropriate geographical definitions that also take into account the areas of influence of cities.
Defining cities and functional urban areas
Share of population by size of cities
The OECD cities and functional urban areas database publishes indicators for FUAs. The following links provide the list of FUAs by country and the boundaries shapefiles for cities and for FUAs.
Defining cities worldwide
Estimated Functional Urban Areas (eFUAs) offer a way to draw commuting zones around city centres for countries with no available commuting flow data. eFUAs do not follow administrative borders and are available worldwide. This document details the methodology. The boundaries for about 9,000 eFUAs of at least 50,000 inhabitants worldwide can be access here. The report Cities in the World: A New Perspective on Urbanisation presents comparative analysis of FUAs worldwide using this definition.
The OECD Atlas
The OECD Regions and Cities Atlas is a one-stop shop to access and visualise indicators for regions, cities and functional urban areas.