In this article, we describe a research approach to undertaking a small area census to identify informal economy activity, using a mixture of quantitative and qualitative tools. The method focuses on enterprise activity. The approach enables the researcher to record a broader spectrum of informal micro-enterprises through identifying businesses in situ within an area of sufficient scale to broadly reflect area-level market conditions and business dynamics. The approach comprises an enterprise census, a survey of all identified micro-enterprises in key sectors, in-depth interviews, and participatory research techniques. The article reports on the application of this method in eight case sites, located in township settlements within five major cities in South Africa. The research identified 9,400 individual enterprises, entailing 10,220 primary and secondary activities, distributed within a population of 325,000 and comprising 97,000 households. The approach permits significant advances to our understanding of the spatial dynamics of the informal sector. The research data has enabled the researcher to make original contributions to understanding informal enterprise activities in grocery retailing, liquor trade, and traditional medicine sectors.