Land is an important and valuable natural resource, serving both as a store of wealth and as an input in production. Previous attempts to measure the value of land of the United States have focused on indirect measures, inferring values based on the difference between the market value of real property and the replacement value of structures, and have not counted the entirety of the land area of the United States. Instead, this paper takes hedonic estimates of land prices in various locations and interpolates these values to a mosaic of parcels, census tracts, and counties of various sizes in the contiguous (lower 48) United States plus the District of Columbia. Estimates suggest that this 1.89 billion acres of land are collectively worth approximately $23 trillion in 2009 (current prices), with 24% of the land area and $1.8 trillion of the value held by the federal government.