Technical Abstract: Accurate time- and cost-efficient mapping is central to successful rangeland invasive plant management. In this study, sampling and Inverse Distance Weighted (IDW) interpolation modeling was tested as a mapping alternative to expensive full-coverage delineation survey mapping methods. Our objective was to examine accuracies of presence/absence maps generated from 18 sampling strategies (3 sampling methods x 6 sample densities) using IDW. Invasive plant field survey maps with known accuracies were used for generating samples and to test interpolation results at two sites. Site 1 was approximately 6.0 km2 in size, dominated by Russian knapweed (Acroptilon repens L.). Site 2 was an approximately 13.5 km2 upland area dominated by spotted knapweed (Centaurea maculosa Lam). Sampling method x sample density combinations were gathered from the field survey infestation maps using repeated computer-based sampling methods. IDW modeling was applied to each of the sample data sets. Accuracies of the IDW interpolation results were calculated by re-referencing field survey maps. Sampling at density of 0.25 percent (about 1 point per ha) using a systematic sampling method was determined to be the preferred sampling strategy for both sites. This combination of sampling density and method yielded 85% accurate presence/absence maps. We conclude sampling, when combined with ID interpolation modeling, can generate accurate invasive plant maps and is a potential alternative to current delineation survey methods.