The Building Stock Database (BSD) provides county-level estimates and forecasts of the stock of floor space and number of buildings (or dwelling units for residential) for 15 types of nonresidential and residential buildings. The data is in annual totals from 1970 to the present with a forecast for the next five years. This database was first built in 1985 using benchmarks for the floor space in place at that time and annually since then new square footage created from new construction and building additions has been added each year. A demolition factor is also applied to take into consideration square footage lost from the inventory. The BSD can be used and input for measuring building-related demand for energy year over year. It can be useful in estimating the size of the replacement market for various building materials and can be used for determining new markets to enter based on their existing stock of floor space by structure type.