Municipality Idrija, which is part of the Goriška statistical region, measures 294 km2; this ranks it 8th among Slovene municipalities.
Statistical data for 2013 reveal the following:
In the middle of 2013 about 12,000 people (about 6,000 men and 6,000 women) were living in the municipality, which ranks Idrija 44th among Slovene municipalities. The population density was 41 people per square kilometre, which was lower than the national average of 102 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 -0.3 (in Slovenia 0.9). The number of people who moved from the municipality was lower than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was positive. It was 0.6. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 0.3 (in Slovenia 1.1).
The mean age of people in Idrija was 43.2 years, which was higher than the national average (42.2).
As in most Slovene municipalities, in Idrija the number of old people was higher than the number of young people: there were 131 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 119. It also shows that the mean age of people in Idrija 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 Idrija – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was exactly the opposite.
Idrija had 5 kindergarten. They were attended by 487 children or 73% of all children aged 1–5, which was less than the national average of 75%. In the school year 2013/2014 basic schools in Idrija were attended by about 940 pupils, while various upper secondary schools were attended by about 500 pupils. There were 50 students and 8 graduates per 1,000 people in the municipality; in Slovenia the averages were 44 per 1,000 and 9 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 64% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 57%.
The registered unemployment rate was 7.1%, which is less than the national average (13.1%). As in most Slovene municipalities, more women than men were unemployed.
In Idrija, average monthly gross earnings per person employed by legal persons were about 3% lower than the annual average of monthly earnings for Slovenia; and net earnings about 3% lower.
In 2013, there were 417 dwellings per 1,000 population. About 68% of dwellings had at least three rooms. Average size of dwellings in the municipality was 80 m2.
About every other person in Idrija had a car (51 passenger cars per 100 population); cars in this municipality were on average 9 years old.
In 2013, 294 kg of municipal waste per person was collected in Idrija, which is 26 kg less than on average in Slovenia.