The North American Regional Reanalysis (NARR) is a long-term, high-resolution, dynamically consistent atmospheric and land surface hydrology dataset for the North American domain, covering the period from 1979 to 2003. It is an improvement over earlier global reanalysis datasets in both resolution and accuracy. The NARR assimilates high-quality precipitation observations, leading to more accurate forcing for the land-surface model and improved atmospheric circulation. The NARR system includes the NCEP-DOE Global Reanalysis lateral boundaries, the NCEP Eta Model, and the Noah land-surface model. The NARR has been continued in near-real time as the R-CDAS, with minimal changes to minimize technical inhomogeneities. The NARR has shown significant improvements in temperature and wind fits to rawinsonde observations compared to the NCEP-DOE Global Reanalysis (GR2), particularly in the troposphere. The NARR's realistic precipitation patterns and improved moisture budget closure are notable features. The NARR data are being archived and distributed by NCDC, NCAR, and SDSC, with NOMADS at NCDC serving as a major public distributor. The NARR has been widely used for various applications, and its overall quality is confirmed to meet the objectives set for the project.The North American Regional Reanalysis (NARR) is a long-term, high-resolution, dynamically consistent atmospheric and land surface hydrology dataset for the North American domain, covering the period from 1979 to 2003. It is an improvement over earlier global reanalysis datasets in both resolution and accuracy. The NARR assimilates high-quality precipitation observations, leading to more accurate forcing for the land-surface model and improved atmospheric circulation. The NARR system includes the NCEP-DOE Global Reanalysis lateral boundaries, the NCEP Eta Model, and the Noah land-surface model. The NARR has been continued in near-real time as the R-CDAS, with minimal changes to minimize technical inhomogeneities. The NARR has shown significant improvements in temperature and wind fits to rawinsonde observations compared to the NCEP-DOE Global Reanalysis (GR2), particularly in the troposphere. The NARR's realistic precipitation patterns and improved moisture budget closure are notable features. The NARR data are being archived and distributed by NCDC, NCAR, and SDSC, with NOMADS at NCDC serving as a major public distributor. The NARR has been widely used for various applications, and its overall quality is confirmed to meet the objectives set for the project.