In this 22-question activity, high school students investigate the spatial distribution of marijuana stores in Colorado using an interactive web map containing stores, centers, highways, population, and other data at several scales. After completing this lesson, students will know and be able to: (1) Use interactive maps, layers, and tools in ArcGIS Online to answer "the whys of where" to understand the patterns of businesses across a geographic area; (2) Understand that buying, selling, and using marijuana is legal in Colorado and that marijuana stores, like other types of stores, are located where they are as a result of laws, restrictions, population density, demography, consumer behavior, traffic volume, and other geographic considerations; (3) Understand that marijuana stores are located in a wide variety of neighborhoods, from middle-income to wealthy, from rural to suburban to urban; and (4) Understand that the locations of businesses are related to transportation, population, and other variables. A lesson handout is included.