Euphagus carolinus has a large range, breeding across the boreal zone of North America from New England, through Canada to Alaska and winters widely across the south-eastern United States. The population was estimated at 2 million individuals based on data from the North American Breeding Bird Survey collected during the 1980's and 1990's. This figure is now likely to be a considerable overestimate as the species continues to decline. Estimates of the global decline since 1966 vary between 85% and 99%. This ongoing decline follows a longer term decline that began prior to 1950. The reasons for this dramatic decline remain poorly understood.