The IPUMS International Historical Geographic Information System (IHGIS) provides subnational data from agricultural and population and housing censuses from around the world. The agricultural census data cover a wide range of information on agricultural inputs, labor, production, and more, which can be used to explore a variety of research questions. IHGIS data can help understand, for instance, which factors contribute to better crop productivity, including the role of fertilizer use. Researchers have used agricultural census data at the subnational level to analyze the negative relationship between farm size and fertilizer overuse in China (Ju et al. 2016); the relationship between maize yield, farm size and fertilizer and irrigation use in Mexico (LaFevor and Magliocca 2020); the use of chemical fertilizers in direct market farms in the U.S. (Schoolman 2019); and the environmental sustainability of using fertilizers, insecticides and pesticides in Pakistan (Zulfiqar and Thapa 2017).