Estimates of local abundance for declining species provide important information necessary for conservation measures. We estimated the density and abundance of Mountain Plover (Charadrius montanus) in Phillips and Valley counties in north-central Montana in 2004 using distance sampling methodology. Sampling efforts were stratified to include active prairie dog (Cynomys sp.) colonies, an Area of Critical Environmental Concern (ACEC) specifically established for Mountain Plover, and all other habitats. The density of plovers was greatest on prairie dog colonies (7.20 ± 0.42 [SE] plovers/km²) and much lower on both the ACEC (1.60 ± 0.31 plovers/km²), and all other habitats (0.07 ± 0.01 plovers/km²). An estimated 1,028 (95% CI = 903–1,153) plovers inhabited this region in 2004, most (74%) on prairie dog colonies. Our results highlight the importance of prairie dog colonies to plovers in this region and suggest that as much as 10% of their continental population may breed in north-central Montana.