This paper provides an introduction to the practice of community-led enumerations as conducted by Shack/Slum Dwellers International (SDI). It sets out the historical context for enumerations, which came out of a need in India in 1975 to find a more long-term solution to evictions, and charts its subsequent evolution and spread throughout other countries. Enumerations can help to build a community, define a collective identity, facilitate development priority setting and provide a basis for engagement between communities and government on planning and development.