Municipality Trzin, which is part of the Osrednjeslovenska statistical region, measures 9 km2; this ranks it 209th among Slovene municipalities.
Statistical data for 2008 reveal the following:
At the end of 2008 about 3,600 people (about 1,800 men and 1,800 women) were living in the municipality, which ranks Trzin 136th among Slovene municipalities. The population density was 428 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 9.0 (in Slovenia 1.7). 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 2.2. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 11.2 (in Slovenia 10.9).
The mean age of people in Trzin was 39.1 years, which was lower than the national average (41.3 years).
In contrast to most Slovene municipalities, in Trzin the number of young people was higher than the number of old people: there were 72 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was lower than the national average of 118. It also shows that the mean age of people in Trzin is growing more slowly 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 Trzin – in contrast to most Slovene municipalities – fewer women were 65+ years old than 14 or less; for men the situation was the same.
Trzin had 1 kindergarten. It was attended by 200 children. Of all children aged 1–5, 85% were included in kindergartens, which was more than the national average of 70%. In the school year 2008/09 elementary school in Trzin was attended by about 390 pupils. About 130 pupils from the municipality attended various secondary schools. There were 70 students and 12 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 65% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 62%.
The registered unemployment rate was 3.3%, which is less than the national average (6.7%). As in most Slovene municipalities, more women than men were unemployed.
In Trzin, 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 4% lower.
Every 55th 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 3,317 per capita) was higher than the national average (EUR 3,165 EUR per capita).
In 2008, there were 352 dwellings per 1,000 population. About 76% of dwellings had at least three rooms. Average size of dwellings in the municipality was 93 m2.
Every person in Trzin had a car (71 passenger cars per 100 population); cars in this municipality were on average 6 years old.
In 2008, 761 kg of municipal waste per person was collected in Trzin, which is 342 kg more than on average in Slovenia.