This paper describes the urban design of the digital city called AlphaWorld. AlphaWorld is a digital community created in 1995 and accessed daily through the internet by thousands of users. Unlike other digital communities, AlphaWorld’s users may also settle land and construct objects within the world. The design and content of these constructions are determined autonomously, and the cumulative result of this settlement is an organically evolved digital city. AlphaWorld’s urban form differs substantially from real-world cities in the absence of many of the constraints which govern the design of those cities: permanent population, land cost, zoning and transportation. The paper examines AlphaWorld’s urban design at both the regional and neighbourhood scale. At the regional scale, settlement in AlphaWorld is highly concentrated at its centre but highly deconcentrated elsewhere because of transportation constraints. At the neighbourhood scale, AlphaWorld lacks organizing design features and is very low-density because land has no cost and is settled in an ad hoc fashion. The resulting urban fabric is visually chaotic and difficult to navigate. The freedom of settlement action offered by AlphaWorld allows for individual creativity at the cost of larger-scale urban order. The paper concludes by placing AlphaWorld in the context of real-world urban places. Three urban theories—ideal morphologies, heterotopia and self-organizing systems—show that AlphaWorld is unlike any real-world city but reflects many elements of real-world urban design.