Municipality Trzin, which is part of the Osrednjeslovenska statistical region, measures 9 km2; this ranks it 209th among Slovene municipalities.

Statistical data for 2010 reveal the following:

In the middle of 2010 about 3,800 people (about 1,850 men and 1,950 women) were living in the municipality, which ranks Trzin 133rd among Slovene municipalities. The population density was 442 people per square kilometre, which was higher than the national average of 101 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 5.5 (in Slovenia 1.8). 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 12.4. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 17.9 (in Slovenia 1.6).

The mean age of people in Trzin was 39.9 years, which was lower than the national average (41.6).

In contrast to most Slovene municipalities, in Trzin the number of young people was higher than the number of old people: there were 82 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 117. 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 2 kindergartens. They were attended by 249 children or 83% of all children aged 1–5, which was more than the national average of 74%. In the school year 2010/2011 elementary school in Trzin was attended by about 390 pupils, while various upper secondary schools were attended by about 150 pupils. There were 59 students and 8 graduates per 1,000 people in the municipality; in Slovenia the averages were 52 per 1,000 and 10 per 1,000, respectively.

Among people aged 15–64 (i.e. working age population) about 63% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 59%.

The registered unemployment rate was 6.5%, which is less than the national average (10.7%). 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 12% lower than the annual average of monthly earnings for Slovenia; and net earnings about the same percentage.

Every 56th person in the municipality was receiving at least one financial social assistance. In Slovenia as a whole every 22nd person received at least one financial social assistance.

The value of gross investment in new fixed assets in the municipality (EUR 3,623 per capita) was higher than the national average (EUR 2,176 per capita).

In 2010, there were 348 dwellings per 1,000 population. About 74% of dwellings had at least three rooms. Average size of dwellings in the municipality was 92 m2.

Every person in Trzin had a car (70 passenger cars per 100 population); cars in this municipality were on average 6 years old.

In 2010, 860 kg of municipal waste per person was collected in Trzin, which is 471 kg more than on average in Slovenia.