This paper describes the development of a 2° latitude × 3° longitude grid of summer drought reconstructions for the continental United States, based on a dense network of annual tree-ring chronologies. The drought metric used is the Palmer Drought Severity Index (PDSI). The grid contains 154 points and covers the period 1700–1978. An automated gridpoint regression method called "point-by-point regression" was developed and tested to produce the grid. The reconstructions have been thoroughly tested for validity using PDSI data not used in regression modeling. Most of the gridpoint estimates of drought pass the verification tests. The spatial features of drought in the United States have been faithfully recorded in the reconstructions. The drought reconstructions show that the 1930s "Dust Bowl" drought was the most severe such event to strike the United States since 1700. Other more local droughts are also revealed in the regional patterns of drought obtained by rotated principal component analysis. These reconstructions are located on a NOAA Web site at the World Data Center-A in Boulder, Colorado, and can be freely downloaded from there. The PDSI grid used in this study is 2° latitude × 3° longitude and is based on 1036 single-station monthly PDSI records estimated from the Historical Climatology Network. The grid is shown in Fig. 1. The choice of the gridding dimension was a trade-off between spatial resolution and the desire to reduce the size of the PDSI network. A 2° × 3° grid reduces the PDSI network to about 15% of its original size. Yet, the spatial definition of the grid should still be high enough to capture mesoscale patterns of wetness and dryness and to resolve regional drought patterns found by KK using a coarser 60-point PDSI grid. The tree-ring chronologies used here to reconstruct past drought across the continental U.S. number 425. Many of the new chronologies were developed after the start of that study. Others were not included for a variety of reasons. We have chosen to include virtually all available chronologies that begin no later than 1700 and end no earlier than 1979. Figure 2 shows the distribution of sites across the United States. The distribution is highly patchy due, in part, to the uneven distribution of forested land. The method used to reconstruct the PDSI grid from tree rings is point-by-point regression (PPR). As implemented here, PPR is simply the sequential, automated fitting of single-point principal components regression models of tree rings to a grid of climate variables. The sequential nature of PPR differentiates it from joint space–time methods used to simultaneously relate two fields of variables. The PPR method is based on the premise that only those tree-ringThis paper describes the development of a 2° latitude × 3° longitude grid of summer drought reconstructions for the continental United States, based on a dense network of annual tree-ring chronologies. The drought metric used is the Palmer Drought Severity Index (PDSI). The grid contains 154 points and covers the period 1700–1978. An automated gridpoint regression method called "point-by-point regression" was developed and tested to produce the grid. The reconstructions have been thoroughly tested for validity using PDSI data not used in regression modeling. Most of the gridpoint estimates of drought pass the verification tests. The spatial features of drought in the United States have been faithfully recorded in the reconstructions. The drought reconstructions show that the 1930s "Dust Bowl" drought was the most severe such event to strike the United States since 1700. Other more local droughts are also revealed in the regional patterns of drought obtained by rotated principal component analysis. These reconstructions are located on a NOAA Web site at the World Data Center-A in Boulder, Colorado, and can be freely downloaded from there. The PDSI grid used in this study is 2° latitude × 3° longitude and is based on 1036 single-station monthly PDSI records estimated from the Historical Climatology Network. The grid is shown in Fig. 1. The choice of the gridding dimension was a trade-off between spatial resolution and the desire to reduce the size of the PDSI network. A 2° × 3° grid reduces the PDSI network to about 15% of its original size. Yet, the spatial definition of the grid should still be high enough to capture mesoscale patterns of wetness and dryness and to resolve regional drought patterns found by KK using a coarser 60-point PDSI grid. The tree-ring chronologies used here to reconstruct past drought across the continental U.S. number 425. Many of the new chronologies were developed after the start of that study. Others were not included for a variety of reasons. We have chosen to include virtually all available chronologies that begin no later than 1700 and end no earlier than 1979. Figure 2 shows the distribution of sites across the United States. The distribution is highly patchy due, in part, to the uneven distribution of forested land. The method used to reconstruct the PDSI grid from tree rings is point-by-point regression (PPR). As implemented here, PPR is simply the sequential, automated fitting of single-point principal components regression models of tree rings to a grid of climate variables. The sequential nature of PPR differentiates it from joint space–time methods used to simultaneously relate two fields of variables. The PPR method is based on the premise that only those tree-ring