This paper reports on current progress in estimating the dimensions and attributes of global urban expansion. Monitoring global urban expansion is undertaken by a partnership between the NYU Urban Expansion Program, the United Nations Human Settlements Programme (UN Habitat), and the Lincoln Institute of Land Policy. Results are expected in time for Habitat III, the United Nations Conference on Housing and Sustainable Urban Development, now scheduled for October 2016. The monitoring effort focuses on a global stratified samle of 200 cities, selected from a universe of 4,245 cities that had 100,000 people or more in 2010. It consists of a four-phase research project. Phase I focuses on the mapping and measurement of global urban expansion in the sample of cities, 1990 - 2014, using Landsat satellite imagery; Phase II on the mapping and measurement of urban layouts in the sample, 2014-2015, using high-resolution satellite imagery; Phase III on a land and housing survey focused on the regulatory regimes and on land and housing affordability using city-based researchers in the global sample of cities; and Phase IV, to be completed later, on the mapping and estimation of urban extent in the entire universe of cities to 2045.