Of the rest of the land, 7% is settled (buildings or roads) and the remainder (0.1%) is non-productive (rivers or lakes).

It consists of the village of Muolen and multiple hamlets as well as part of the Hudelmoos, the last high moorland in the Fürstenland (a historic region comprising the Wahlkreises of Wil, St. Gallen and Rorschach).

The blazon of the municipal coat of arms is Per fess Or a Semi Mill-wheel Sable and vert a bar wavy Argent.

Of the foreign population, (as of 2000[update]), 6 are from Germany, 11 are from Italy, 12 are from ex-Yugoslavia, 6 are from Austria, and 11 are from another country.

[8] The age distribution, as of 2000[update], in Muolen is; 164 children or 15.3% of the population are between 0 and 9 years old and 166 teenagers or 15.5% are between 10 and 19.

[4] Out of the total population in Muolen, as of 2000[update], the highest education level completed by 249 people (23.2% of the population) was Primary, while 369 (34.4%) have completed their secondary education, 116 (10.8%) have attended a Tertiary school, and 30 (2.8%) are not in school.

[8] The historical population is given in the following table:[3] The Kulturlandschaft Unteregg/Rotzenwil/Hueb (Cultural region Unteregg/Rotzenwil/Hueb) in the municipality is designated as part of the Inventory of Swiss Heritage Sites.

[12] From the 2000 census[update], 747 or 69.6% are Roman Catholic, while 227 or 21.1% belonged to the Swiss Reformed Church.