The January Map of the Month shows the change in urban development in the East-West Gateway region between 1985 and 2023, according to the Impervious Descriptor data from the National Land Cover Database (NLCD). This dataset uses Landsat satellite imagery and deep-learning algorithms to map urban development, providing a comprehensive view of land use changes over time. Urban development is identified by the presence of impervious surfaces, which include artificial structures like pavements, concrete, and rooftops. The map provides a visual narrative of how the region’s urban footprint has evolved over nearly four decades.
St. Charles County led the expansion, adding approximately 30,739 acres (48.0 square miles) of urban land between 1985 and 2023, the most of any county. Madison County followed with an increase of 19,425 acres (30.4 square miles). Monroe County saw more modest growth, with urban land expanding by 4,127 acres (6.4 square miles), marking the smallest change among the counties. The city of St. Louis, which was already fully developed by 1985, had no significant increase or decrease in urban land over this period.
Other counties also saw growth in developed land: St. Clair County added 17,730 acres (27.7 square miles), St. Louis County added 15,777 acres (24.7 square miles), Jefferson County added 12,072 acres (18.9 square miles), and Franklin County added 10,485 acres (16.4 square miles).