Illgau has a population (as of 31 December 2018) of 802.
As of 2007, 1.6% of the population was made up of foreign nationals.
Over the last 10 years the population has grown at a rate of 7%.
Most of the population (as of 2000) speaks German (99.2%), with Albanian being second most common ( 0.3%) and Russian being third ( 0.3%).

As of 2000 the gender distribution of the population was 50.8% male and 49.2% female.
The age distribution, as of 2008, in Illgau is; 242 people or 33.6% of the population is between 0 and 19.
241 people or 33.4% are 20 to 39, and 166 people or 23.0% are 40 to 64.
The senior population distribution is 45 people or 6.2% are 65 to 74.
There are 19 people or 2.6% who are 70 to 79 and 8 people or 1.11% of the population who are over 80.

As of 2000 there are 248 households, of which 71 households (or about 28.6%) contain only a single individual.
31 or about 12.5% are large households, with at least five members.

In the 2007 election the most popular party was the SVP which received 53.9% of the vote.
The next three most popular parties were the CVP (36.4%), the SPS (5.5%) and the FDP (1.7%).

The entire Swiss population is generally well educated.
In Illgau about 55.2% of the population (between age 25-64) have completed either non-mandatory upper secondary education or additional higher education (either university or a Fachhochschule).

Illgau has an unemployment rate of 0.96%.
As of 2005, there were 70 people employed in the primary economic sector and about 28 businesses involved in this sector.
63 people are employed in the secondary sector and there are 8 businesses in this sector.
71 people are employed in the tertiary sector, with 14 businesses in this sector.

From the 2000 census, 698 or 96.8% are Roman Catholic, while less than 5 people belonged to the Swiss Reformed Church.
There are 6 (or about 0.83% of the population) who are Islamic.
9 (or about 1.25% of the population) belong to no church, are agnostic or atheist, and 6 individuals (or about 0.83% of the population) did not answer the question.

The historical population is given in the following table:
Illgau has a population (as of 31 December 2018) of 802. As of 2007, 1.6% of the population was made up of foreign nationals. Over the last 10 years the population has grown at a rate of 7%. Most of the population (as of 2000) speaks German (99.2%), with Albanian being second most common ( 0.3%) and Russian being third ( 0.3%).
As of 2000 the gender distribution of the population was 50.8% male and 49.2% female. The age distribution, as of 2008, in Illgau is; 242 people or 33.6% of the population is between 0 and 19. 241 people or 33.4% are 20 to 39, and 166 people or 23.0% are 40 to 64. The senior population distribution is 45 people or 6.2% are 65 to 74. There are 19 people or 2.6% who are 70 to 79 and 8 people or 1.11% of the population who are over 80.
As of 2000 there are 248 households, of which 71 households (or about 28.6%) contain only a single individual. 31 or about 12.5% are large households, with at least five members.
In the 2007 election the most popular party was the SVP which received 53.9% of the vote. The next three most popular parties were the CVP (36.4%), the SPS (5.5%) and the FDP (1.7%).
The entire Swiss population is generally well educated. In Illgau about 55.2% of the population (between age 25-64) have completed either non-mandatory upper secondary education or additional higher education (either university or a Fachhochschule).
Illgau has an unemployment rate of 0.96%. As of 2005, there were 70 people employed in the primary economic sector and about 28 businesses involved in this sector. 63 people are employed in the secondary sector and there are 8 businesses in this sector. 71 people are employed in the tertiary sector, with 14 businesses in this sector.
From the 2000 census, 698 or 96.8% are Roman Catholic, while less than 5 people belonged to the Swiss Reformed Church. There are 6 (or about 0.83% of the population) who are Islamic. 9 (or about 1.25% of the population) belong to no church, are agnostic or atheist, and 6 individuals (or about 0.83% of the population) did not answer the question.
The historical population is given in the following table:
Illgau