Municipality Osilnica, which is part of the Jugovzhodna Slovenija statistical region, measures 36 km2; this ranks it 159th among Slovene municipalities.
Statistical data for 2020 reveal the following:
In the middle of 2020 about 350 people (about 190 men and 150 women) were living in the municipality, which ranks Osilnica 212th among Slovene municipalities. The population density was 10 people per square kilometre, which was lower than the national average of 104 people per square kilometre.
The number of live births was lower than the number of deaths, which means that natural increase per 1,000 population in the municipality was negative. It was -8.6 (in Slovenia -2.5). The number of people who moved from the municipality was higher than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was negative. It was -63.4. The sum of natural increase and net migration per 1,000 population in the municipality was negative. It was -72.0 (in Slovenia 6.2).
The mean age of people in Osilnica was 51.4 years, which was higher than the national average (43.6).
As in most Slovene municipalities, in Osilnica the number of old people was higher than the number of young people: there were 393 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was higher than the national average of 136. It also shows that the mean age of people in Osilnica is growing more rapidly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all municipalities except in three (Dobrovnik/Dobronak, Jezersko in Loški Potok) higher than the ageing index for men. In Osilnica – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Osilnica had no kindergartens. Of all children in the municipality aged 1–5, 63% were included in kindergartens, which was less than national average of 81%. In the school year 2020/21 elementary school in Osilnica was attended by fewer than 10 pupils, while various upper secondary schools were attended by fewer than 10 pupils. There were 18 students and no graduates per 1,000 people in the municipality; in Slovenia the averages were 39 per 1,000 and 7 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 49% were persons in employment (i.e. persons in paid employment or self-employed persons), which is less than the national average (66%).
Among 1,000 inhabitants in the municipality, 560 had a passenger car. The car was on average 11 years old.
In 2020, 96 kg of municipal waste per person was collected in Osilnica, which is 259 kg less than on average in Slovenia.