Abstract <p>The highlands of Tokinsko-Stanovoi National Park (established at the end of 2019 with an area of 257 000 hectares in the northern part of Amur oblast at the junction of its borders with Yakutia and Khabarovsk krai) are extremely important for preserving the population of the Okhotsk snow sheep (<i>Ovis nivicola alleni</i> Matschie, 1907), a rare and poorly studied subspecies of snow sheep or bighorn sheep, listed in the Red Books of Amur oblast (2020) and Yakutia (2003). This animal is the primary edificator of the mountain heaths of the Stanovoi Range, which are characterized by a moisture deficit. In Amur oblast, snow sheep inhabit a relatively narrow strip of the Tokinsko-Stanovoi highlands (the eastern section of the Stanovoi Range) 5–15 km wide, stretching along the northern border of Amur oblast from the headwaters of the Okonon River in the west to the headwaters of the Maya River in the east. In addition, they are regularly observed in some areas of Dzhugdyr ridge. The bulk of the population in this region is concentrated in the territory of the national park. The data on the spatial distribution, abundance, and age–sex composition of snow sheep presented in the article were obtained during expeditions in 1992, 1993, 2009, 2018, and 2020–2024. The following were noted: uneven distribution on the mountain heaths of Tokinsko-Stanovoi (higher population density in the central part and lower density on the outskirts of the mountainous country), features of the seasonal distribution, and use of large natural mineral licks (significant concentrations on salt licks in the first half of summer). The observation results indicate the extreme living conditions of the group, determined by the harsh climate of the highlands. The proportion of yearlings (8.3–17.4%) and adult males (9.1–18.2%) is significantly lower than in other, even more northern populations of this species. Disturbances in the age and sex structure may also be associated with the consequences of intensive trophy hunting carried out in recent years before the establishment of the national park (2016–2019). The park has organized effective protection of bighorn sheep, but hunting for them is still permitted in the adjacent territory of Khabarovsk krai. To maintain the sustainability of the population in the region, additional measures are needed to protect and study this species: the creation of a buffer zone of the Tokinsko-Stanovoi National Park, the establishment of Bolshoe Toko Lake National Park in Yakutia, the creation of a wildlife refuge in the Ayano-Maiskii District of Khabarovsk krai on the northern macroslope of the Stanovoi Range, and a survey of Dzhugdyr ridge. It is advisable to study the age and sex structure of bighorn sheep in the first half of summer, when they are concentrated on mineral licks, and to count their numbers in the second half of summer, when they are relatively evenly distributed across the territory.</p>