Majewicz, KarenMartindale, JaimeKernik, MelindaMattke, Ryan2024-09-302024-09-302024-09-12Majewicz, K., Martindale, J., Kernik, M., & Mattke, R. (2024). Ephemeral Geodata: An Impending Digital Dark Age. Journal of Map & Geography Libraries, 1–26. https://doi.org/10.1080/15420353.2024.2398542https://hdl.handle.net/11299/265741Article preprint, 25 pages.Despite the unprecedented rate of geospatial data (“geodata”) generation, we are paradoxically creating a potential “dark age” in geospatial knowledge due to a failure to archive it. In the 20th century, map libraries systematically collected and preserved government-issued maps. However, many have not expanded to include digital formats, which have replaced paper maps in most domains. Compounding this issue is the prevailing practice among government data providers to continuously update public data without adequately preserving previous iterations, thus overwriting the historical record. Consequently, a pronounced gap has emerged in the availability of geospatial information, spanning from the end of the paper map era to the recent past. If unaddressed, this gap is poised to widen, severely impeding future longitudinal research. This paper assesses the current and predicted availability of state and local geographic information across various locations and time periods, analyzing academic map collections and public geodata. Central to our argument is the role of academic libraries in bridging this gap by collecting and preserving yesterday’s geodata. We advocate for libraries to ensure that historical geodata will be accessible for future scholars.en-USgeospatial datadigital archivingdata archivingephermal datamap librariesArticle10.1080/15420353.2024.2398542