Wile 8) srk stad r * pantee od Salaun se elke oh at aah ae omee ' a ABSTRACT A5" x 3" NaI(T1) detector and a high pressure ionization chamber have been used to obtain gamma ray spectra and total gamma dose rates at approximately 100 locations during the course of several survey trips in the southeastern, and western United States. central, Reasonably precise estimates of the dose rates from each of the individual components of both the natural and fallout gamma fields are made using the pulse height spectra and rela- tively simple methods of analysis. The equipment and types of locations surveyed are discussed briefly and the methods used for determining component and total dose rates from the pulse height spectra are summarized. The total terrestrial dose rates as well as the partial dose rates from the uranium-238 series, thorium-232 series, potassium-40, zirconium-niobium-95, and rhodium-106 are tabulated for each location. Particular results of interest with respect to environmental gamma radiation,effects of precipitation on fallout gamma dose rates, and the validity of the spectral analysis methods are discussed. Among these results are the relatively high natural dose rate levels in the Denver, Colorado area and the correlation between fallout gamma dose rates and mean annual rainfall for several sites on the Olympic Peninsula, Washington.