Population status of moose is important for managers of Yukon Flats National Wildlife Refuge because this species is an important source of food for people, and densities on the Refuge are among the lowest in North America. The most recent survey was completed in November/December 2018. This was the first fall survey since 2015. Moose were counted in 97 of 421, 5.3 mi2 units, of which 63 were stratified high-moose density and 34 low-moose density. The estimate for the 2,269 mi2 survey area in the western Yukon Flats Game Management Unit 25D was 1,123 total-observable moose (95% CI; 895-1351).  Density of moose was 0.49/mi2 or 0.19/km2.  The population was comprised of an estimated 908 adults (95% CI; 698-1118) and 199 calves (148-251). The estimate of total-observable moose increased from the lows of 2004-2010. Improved calf survival may have contributed to the population increase in some years. It is unlikely that public harvest of wolves and bears contributed, as harvest intensity is light. Thus, moose density increased in the presence of lightly-harvested wolf and bear populations, suggesting that the dynamics of this low-density population may sometimes be more complex than previously thought. Moose numbers can fluctuate naturally within a low-density equilibrium over a period of approximately a decade, and this fluctuation can be detected with the current survey method.