For a broader study of the climate drivers of regional-fire years in the Northern Rockies, we reconstructed a history of surface fires at 21 sites in Idaho and western Montana. We targeted sites that historically sustained frequent surface fires and were dominated or codominated by ponderosa pine (Pinus ponderosa P. & C. Lawson). Our objective is to report the site-specific fire and site information we did not report in our regional study that might be useful to local land managers for determining such things as Fire Regime Condition Class. We include 23 sites-20 from our regional study (one was reported elsewhere) and another three sampled in the region for other purposes. We cross-dated samples from 640 trees to obtain calendar years for each tree ring and hence for 9,691 fire scars. For each site, we report the chronology of surface fires, properties of the fire regime (mean fire interval and intra-ring position of fire scars), and forest type, as well as topography that might be used to extrapolate site-specific fire regimes to unsampled areas.