Marbach had a population (as of 2011) of 1,217. , 1.7% of the population was made up of foreign nationals. Over the last 10 years the population has decreased at a rate of -11.5%. Most of the population () speaks German (97.8%), with Portuguese being second most common (0.6%) and Serbo-Croatian being third (0.4%). In the 2007 election the most popular party was the
CVP which received 55% of the vote. The next three most popular parties were the
FDP (20.5%), the
SVP (19.7%) and the
SPS (2.4%). The age distribution in Marbach is; 254 people or 21.3% of the population is 0–19 years old. 303 people or 25.4% are 20–39 years old, and 416 people or 34.9% are 40–64 years old. The senior population distribution is 167 people or 14% are 65–79 years old, 45 or 3.8% are 80–89 years old and 8 people or 0.7% of the population are 90+ years old. The entire Swiss population is generally well educated. In Marbach about 52.4% of the population (between age 25–64) have completed either non-mandatory
upper secondary education or additional higher education (either university or a
Fachhochschule). there are 444 households, of which 134 households (or about 30.2%) contain only a single individual. 59 or about 13.3% are large households, with at least five members. 49.5% of the population of the municipality were employed in some capacity. At the same time, females made up 37.1% of the workforce. the religious membership of Marbach was; 859 (73.1%) were Roman Catholic, and 238 (20.3%) were Protestant, with an additional 1 (0.09%) that were of some other Christian faith. There are 8 individuals (0.68% of the population) who are Muslim. Of the rest; there were 5 (0.43%) individuals who belong to another religion, 13 (1.11%) who do not belong to any organized religion, 51 (4.34%) who did not answer the question. ==Weather==