Rossa is a municipality in the Moesa Region in the canton of the Grisons in Switzerland. Its official language is Italian.
Rossa is first mentioned in 1694.
Rossa has an area, , of . Of this area, 9.1% is used for agricultural purposes, while 40.8% is forested. Of the rest of the land, 0.4% is settled (buildings or roads) and the remainder (49.7%) is non-productive (rivers, glaciers or mountains).
Before 2017, the municipality was located in the Calanca sub-district of the Moesa district, after 2017 it was part of the Moesa Region. It is the highest municipality of Val Calanca.
Rossa has a population (as of ) of . , 10.7% of the population was made up of foreign nationals. Over the last 10 years the population has decreased at a rate of -14.4%. Most of the population () speaks Italian (84.1%), with German being second most common (11.4%) and French being third ( 3.0%).
, the gender distribution of the population was 50.4% male and 49.6% female. The age distribution, , in Rossa is; 5 children or 3.8% of the population are between 0 and 9 years old. 6 teenagers or 4.5% are 10 to 14, and 2 teenagers or 1.5% are 15 to 19. Of the adult population, 11 people or 8.3% of the population are between 20 and 29 years old. 9 people or 6.8% are 30 to 39, 23 people or 17.4% are 40 to 49, and 19 people or 14.4% are 50 to 59. The senior population distribution is 17 people or 12.9% of the population are between 60 and 69 years old, 22 people or 16.7% are 70 to 79, there are 14 people or 10.6% who are 80 to 89, and there are 4 people or 3.0% who are 90 to 99.
In the 2007 federal election the most popular party was the SP which received 37.2% of the vote. The next two most popular parties were the SVP (21.5%) and the FDP (20.2%).
In Rossa about 69.3% of the population (between age 25-64) have completed either non-mandatory upper secondary education or additional higher education (either university or a Fachhochschule).
Rossa has an unemployment rate of 2.22%. , there were 4 people employed in the primary economic sector and about 3 businesses involved in this sector. 6 people are employed in the secondary sector and there are 2 businesses in this sector. 8 people are employed in the tertiary sector, with 4 businesses in this sector.
The historical population is given in the following table: