Yellowstone volcano has had three major caldera forming eruption in the last 2.1 million years. Based on ashfall and isotopic dating methods, scientists were able to date the last caldera forming eruption at Yellowstone to about 631,000 years ago. Other isotopic analysis on different layers of ash found across the continental United States show that caldera forming eruptions occur at Yellowstone volcano every 600,000 to 800,000 years. This means that in the next 200,000 years there is a possibility of a caldera forming eruption. For the states boarding Yellowstone National Park, the time it takes for the predicted ashfall to reach the capital cities could mean there is time to evacuate the area before catastrophe strikes. The purpose of this investigation is to determine how long it will take the ashfall from a Yellowstone eruption to reach the capital cities of Montana, Idaho, Utah, Colorado, Nebraska, South Dakota, and Wyoming using wind speed and direction. To conduct this investigation there are specific data that are needed: wind speed and wind direction for the year 2021 form ASOS, state shapefiles, capital city shapefiles, and location of Yellowstone volcano. Conversion tools such as project, XY to Feature, and Feature to Raster were used during this investigation. Data analysis tools such as Zonal Statistics, Buffer, Clip, Distance and Direction, and Raster Calculator were also used. After completion of data analysis, the time it takes ashfall to reach capital city was calculated using wind speed in mph and distance in miles. For the seven states, it will take between 24 to 86 hours for the ashfall to reach each capital city. Depending on location, this could be critical time needed to cover windows and doors to protect from ash, and gather supplies needed to stay indoors for as long as possible.