Grono is first mentioned in 1219 as de Grono. In 1395 it was mentioned as de Agrono.
Leggia
Leggia is first mentioned in 1295 as de Legia.
Verdabbio
Verdabbio is first mentioned in 1203 as Vertabio.
Geography
After the 2017 merger Grono had an area of. Before the merger Grono had an area, of. Of this area, about 8.6% is used for agricultural purposes, while 58.4% is forested. Of the rest of the land, 4.5% is settled and 28.5% is unproductive land. In the 2004/09 survey a total of or about 3.0% of the total area was covered with buildings, an increase of over the 1983 amount. Of the agricultural land, is used for orchards and vineyards, is fields and grasslands and consists of alpine grazing areas. Since 1983 the amount of agricultural land has decreased by. Over the same time period the amount of forested land has increased by. Rivers and lakes cover in the municipality. Before 2017, the municipality was located in the Roveredo sub-district of the Moesa district, after 2017 it was part of the Moesa Region. The village is on the right bank of the Moesa river by the mouth of the Calanca.
Demographics
After the 2017 merger Grono has a population of. , 32.3% of the population are resident foreign nationals. In 2015 a small minority was born in Italy and 89 or 8.7% of the population was born in Portugal. Over the last 4 years the population has changed at a rate of 6.72%. The birth rate in the municipality, in 2014, was 13.9, while the death rate was 7.0 per thousand residents. , the gender distribution of the population was 51.4% male and 48.6% female. The age distribution,, in Grono is; 93 children or 10.2% of the population were between 0 and 9 years old. 40 teenagers or 4.4% were 10 to 14, and 40 teenagers or 4.4% were 15 to 19. Of the adult population, 107 people or 11.7% of the population were between 20 and 29 years old. 130 people or 14.2% were 30 to 39, 145 people or 15.8% were 40 to 49, and 138 people or 15.1% were 50 to 59. The senior population distribution was 87 people or 9.5% of the population were between 60 and 69 years old, 68 people or 7.4% were 70 to 79, there were 58 people or 6.3% who were 80 to 89, and there were 10 people or 1.1% who were 90 to 99. In 2015 there were 385 single residents, 507 people who were married or in a civil partnership, 56 widows or widowers and 72 divorced residents. In 2014 there were 428 private households in Grono with an average household size of 2.32 persons. Of the 273 inhabited buildings in the municipality, in 2000, about 63.7% were single family homes and 15.8% were multiple family buildings. Additionally, about 24.2% of the buildings were built before 1919, while 13.2% were built between 1991 and 2000. In 2013 the rate of construction of new housing units per 1000 residents was 2.01. The vacancy rate for the municipality,, was 0.76%. The historical population is given in the following table:
year
population
1773
296
1850
517
1900
484
1950
528
2000
916
Heritage sites of national significance
The Torre Fiorenzana is listed as a Swissheritage site of national significance. The Torre Fiorenzana was built about the end of the 12th century for the Sacco family. It is a five story tower house with a rectangular footprint. In 1406 it was the site of the murder of Alberto de Sacco. In 1977 it was restored and is now owned by the Museo moesano.
Climate
The nationwide record temperature of was registered in Grono during the 2003 European heat wave on 11 August 2003. Between 1961 and 1990 Grono had an average of 102.3 days of rain per year and on average received of precipitation. The wettest month was August during which time Grono received an average of of precipitation. During this month there was precipitation for an average of 10.1 days. The month with the most days of precipitation was May, with an average of 12.9, but with only of precipitation. The driest month of the year was December with an average of of precipitation over 10.1 days.
Economy
Grono is an industrial-tertiary municipality, a municipality where agriculture and manufacturing play a minor role in the economy. , there were a total of 825 people employed in the municipality. Of these, a total of 6 people worked in 5 businesses in the primary economic sector. The secondary sector employed 343 workers in 35 separate businesses. A minority of the secondary sector employees worked in very small businesses. There were 7 small businesses with a total of 214 employees and one mid-sized business with a total of 56 employees. Finally, the tertiary sector provided 476 jobs in 131 businesses. There were two mid-sized businesses with a total of 137 employees. In 2014 a total of 2.% of the population received social assistance.
Politics
In the 2015 federal election the most popular party was the SVP with 41.0% of the vote. The next three most popular parties were the SP, the CVP and the FDP. In the federal election, a total of 212 votes were cast, and the voter turnout was 35.7%. The 2015 election saw a large change in the voting when compared to 2011. The percentage that the CVP received dropped from 29.2% to 18.7%, while the percentage of the vote received by the SVP increased sharply from 22.2% in 2011 to 41.0%. In the 2007 federal election the most popular party was the SVP which received 32.6% of the vote. The next three most popular parties were the SP, the CVP and the FDP.
Education
In Grono about 56.4% of the population have completed either non-mandatory upper secondary education or additional higher education.
Crime
In 2014 the crime rate, of the over 200 crimes listed in the Swiss Criminal Code, in Grono was 50.2 per thousand residents, slightly lower than the national average. There were no drug crimes nor violations of immigration, visa and work permit laws.
