Municipality Mežica, which is part of the Koroška statistical region, measures 26 km2; this ranks it 187th among Slovene municipalities.
Statistical data for 2008 reveal the following:
At the end of 2008 about 3,700 people (about 1,900 men and 1,800 women) were living in the municipality, which ranks Mežica 135th among Slovene municipalities. The population density was 140 people per square kilometre, which was higher than the national average of 100 people per square kilometre.
The number of live births was higher than the number of deaths, which means that natural increase per 1,000 population in the municipality was positive. It was 4.5 (in Slovenia 1.7). 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 -22.5. The sum of natural increase and net migration per 1,000 population in the municipality was negative. It was -17.9 (in Slovenia 10.9).
The mean age of people in Mežica was 43.2 years, which was higher than the national average (41.3 years).
As in most Slovene municipalities, in Mežica the number of old people was higher than the number of young people: there were 142 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 118. It also shows that the mean age of people in Mežica is growing more rapidly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all Slovene municipalities higher than the ageing index for men. In Mežica – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Mežica had 1 kindergarten. It was attended by 94 children. Of all children aged 1–5, 66% were included in kindergartens, which was less than the national average of 70%. In the school year 2008/09 elementary school in Mežica was attended by about 290 pupils. About 150 pupils from the municipality attended various secondary schools. There were 60 students and 6 graduates per 1,000 people in the municipality; in Slovenia the averages were 55 per 1,000 and 8 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 57% were persons in employment (i.e. persons in paid employment or self-employed persons), which is less than the national average of 62%.
The registered unemployment rate was 6.8%, which is more than the national average (6.7%). As in most Slovene municipalities, more women than men were unemployed.
In Mežica, average monthly gross earnings per person employed by legal persons were about 11% lower than the annual average of monthly earnings for Slovenia; and net earnings about 9% lower.
Every 28th person in the municipality was receiving at least one financial social assistance. In Slovenia as a whole every 28th person received at least one financial social assistance.
The value of gross investment in new fixed assets in the municipality (EUR 2,529 per capita) was lower than the national average (EUR 3,165 EUR per capita).
In 2008, there were 420 dwellings per 1,000 population. About 41% of dwellings had at least three rooms. Average size of dwellings in the municipality was 70 m2.
Every other person in Mežica had a car (46 passenger cars per 100 population); cars in this municipality were on average 8 years old.
In 2008, 416 kg of municipal waste per person was collected in Mežica, which is 3 kg less than on average in Slovenia.