The primary format used to deliver the dataset found in Giles and others, 2009, Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems: USGS Data Series 433 is Microsoft Access. This dataset was created in two other formats in order to facilitate wider usage for users who may prefer formats other than Access. Strong attempts were made to avoid inevitable data corruption caused by the reformatting of this dataset into other formats. These data are released on the condition that neither the U.S. Geological Survey (USGS) nor the U.S. Government may be held liable for any damages resulting from authorized or unauthorized use. The dataset in .mdb form (NSP.mdb) may be accessed using Microsoft Access 2000, 2002, 2003, or 2007. The Near-Surface Processes database (NSP.mdb) contains thirteen relational datasets. These datasets comprise all of the data collected as part of the study and all of the data discussed in this report. From these datasets, eighteen analytical data tables were created of various sections of data. These eighteen "ChemData" tables each represent a unique dataset containing analytical data gathered through the analysis of specific sample media and determined by certain analytic methods (media/method specific datasets). Though this is a certain advantage to the "flatfile" or spreadsheet user, it must be stressed that the parameters and criteria for these datasets were chosen by the database designer and may not meet the specific requirements of the spreadsheet user for geospatial modeling. A table of mineral deposit models and a related table of references were created to assist the user in understanding the various types of mineral deposits represented in this study. A table of data field name definitions was also created from the data sets. Data were collected at 3,126 sites. The database includes 429,211 results for 6,580 water samples, 1,572 rock samples, 1,543 soil samples, 1,011 sediment samples, 399 sediment concentrate samples, 159 vegetation samples, and 134 mineral samples. These entries contain quantitative, qualitative, or descriptive measurements. Data definition is provided through the use of 509 unique parameters, or measurement types. The dataset in .xls form (NSP_Excel_Files) may be accessed using Microsoft Excel 2000, 2002, 2003 or 2007. Most of the Access datasets in the NSP database were exported into Excel as 31 spreadsheets for use by the non-database user so that all of the data is presented in Excel spreadsheet format. From these Access datasets, eighteen analytical data tables were created of various sections of data. These eighteen "ChemData" tables each represent a unique dataset containing analytical data gathered through the analysis of specific sample media and determined by certain analytic methods (media/method specific datasets). These eighteen analytical data tables were reformatted as Excel spreadsheets. Though this is a certain advantage to the spreadsheet user, it must be stressed that the parameters and criteria for these datasets were chosen by the database designer and may not meet the specific requirements of the spreadsheet user for geospatial modeling. The intended relationships between the spreadsheets and their fields (columns) can be best understood by consulting the relationship diagram in figure 1, "Table relationships in the Near Surface Processes database", found in Giles and others, 2009, Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems: USGS Data Series 433. The dataset in ASCII flatfile form (NSP_ASCII_Files) may be accessed using any text editor, but is best used by loading each flatfile into a relational database and re-establishing the links as shown in figure 1, "Table relationships in the Near Surface Processes database", found in Giles and others, 2009, Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems: USGS Data Series 433. Metadata provides information about the geospatial data such as its content, quality, condition, and other characteristics of data. Metadata has been provided (NSPMetadata) as .txt, .xml and .html files to facilitate use by various software programs.