The City of St. Louis (which is an independent city separate from St. Louis County) has a well documented pattern of extensive vacancy. What is not well known, however, is the actual number of vacancies in the city. A variety of estimates have been made in the last several decades. Most recently, the Mayor’s office released an estimate of at least 24,000 vacant properties as part of the City’s Preliminary Resilience Assessment. Our Urban Prairies project aims to produce estimates of vacancy at the parcel level in St. Louis. As of January 2017, we believe that there are between 32,431 (25%) and 48,013 (37%) vacant parcels out of a total of 128,644. We are particularly interested in how vacant land clusters spatially to produce areas in St. Louis that appear to ‘return to nature’.