Municipality Idrija, which is part of the Goriška statistical region, measures 294 km2; this ranks it 8th among Slovene municipalities.
Statistical data for 2009 reveal the following:
In the middle of 2009 about 11,900 people (about 5,900 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 101 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 muncipality was negative. It was -1.3 (in Slovenia 1.5). 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 -1.7. The sum of natural increase and net migration per 1,000 population in the municipality was negative. It was -3.0 (in Slovenia 7.2).
The mean age of people in Idrija was 42.6 years, which was higher than the national average (41.4 years).
As in most Slovene municipalities, in Idrija the number of old people was higher than the number of young people: there were 132 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 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 6 kindergartens. They were attended by 349 children or 61% of all children aged 1–5, which was less than the national average of 72%. In the school year 2009/10 elementary schools in Idrija were attended by about 990 pupils, while various upper secondary schools were attended by about 540 pupils. There were 60 students and 9 graduates per 1,000 people in the municipality; in Slovenia the averages were 56 per 1,000 and 9 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 65% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 61%.
The registered unemployment rate was 4.6%, which is less than the national average (9.1%). In contrast to most Slovene municipalities, more men than women were unemployed.
In Idrija, 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 37th person in the municipality was receiving at least one financial social assistance. In Slovenia as a whole every 23rd person received at least one financial social assistance.
The value of gross investment in new fixed assets in the municipality (EUR 2,560 per capita) was lower than the national average (EUR 2,564 per capita).
In 2009, there were 427 dwellings per 1,000 population. About 57% of dwellings had at least three rooms. Average size of dwellings in the municipality was 75 m2.
About every other person in Idrija had a car (52 passenger cars per 100 population); cars in this municipality were on average 8 years old.
In 2009, 398 kg of municipal waste per person was collected in Idrija, which is 6 kg less than on average in Slovenia.