It is located on the right side of the Serio River in the upper Seriana Valley; during the Middle Ages it was known as the little Toledo thanks to some smithies that turned it into an important centre for iron making and the consequent realization of cold weapons, halberds, shields and armors.

The municipality is made by the centre located on a rock dominating the Serio river, at 676 m above the sea level and by some hamlets nestled along both the mountainous slopes of the valley.

It is divided in four sectors composed by tunnels, hallways and detachments for a total length of 1217 m and a difference in altitude of 189 m up to the deepest point that is the green lake.

This and some traces on weapons and corks witness the presence of inhabitants on the territory up to the Roman period, as well the area was a shelter for the first Italians from the Barbaric invasions.

The first documents about the existence of the village date back to that period too: for the first time the expressions ``vallis Ardexie seu Grumi” or “curia Ardesii er Grummi”,[10] as to point out Ardesio and Gromo as those areas that will be turned into comuni rurali.

After the Peace of Constance of 1183, the valley was donated from Arnolfo count of Austria to Pantaleone Burgente, who by promising the maintenance of some privileges gained the fidelity of the citizens.

In 1252 his nephew Conte Antonio Patavino  gave the land to his brother in law Alessandro Ferrarese, who swore to maintain rights and privileges.

[20] With the occupation of Bergamo and the Province by the Visconti family, the local administration was entrusted by podestàs chosen by the headquarter, and with the Malatesta in 1408 the vicar's function was confirmed, also with the privileges previously established.

It hosts the altarpiece known as The Virgin with the child dating back to 1625 by Enea Salmeggia known as Il Talpino where underneath the Saints Gregory the Great and Charles Borromeo there is the landscape of the ancient Gromo as it was in the 17th century.

Inside, there are many worthy works of art: the north and south naves shows a strong Baroque impact; the presbytery is composed by a gold wooden altar (1645); a choir with 34 caryatids, 6 canvas by Antonio Cifrondi about the martyrdom and death of the patron saints and two golden copper cases containing some valuable relics.

Within the south nave you can find an All Saints’ day altarpiece by Antonio Marinoni, while a polypitch with golden wood frame is hosted on the northern side.

Outside, at the end of the 17th century portico, you can see Saint Benedict's chapel, while nearby you can find the museum safeguarding works connected to Gromo's faith and is dedicated to the Bishop of Brescia Luigi Morstabilini, born in the small hamlet of Ripa.

The small chapel dedicated to the Saint from Nursia was built upon the ancient cemetery that surrounded the parish church in 1454 as decided by the bishop Giovanni Buccelleni.

The church located in the lower part of the hamlet Ripa is dedicated to the visit of Blessed Virgin Mary to her cousin Elizabeth, originally built in 1565 then destroyed in 1945.

The presbytery with barrel ceiling is slightly narrower with respect to the nave and is preceded by a triumphal stone arch laying on square pillars and taking light by the window located on the right.

Two exterior galleries, overlapping the ground floor's portico, the columns with the angle leaves capitals, typical of the Bergamasque's construction, date it back to the first half of 1400.

A circular fountain, already mentioned in some documents of 1399, in white marble decorate the square in front of the palace, that remains one of the few monuments whose Baroque style has not been changed over years.

[21] Located in the central part of the village, along the ancient Milesi street leading to Piazza Dante, it is composed by more units with an inner garden where there were the undergrounds that in the medieval period were used as warehouses for swords and iron planks.

[22][23][24] Along the mule track that leads from the village to Ripa hamlet, we find some villas in a Liberty style dating back to the beginning of the 20th century, realized by Berardo Cittadini and used as private houses.

[25][26] A document dating back to 1428[27] mentions the castle as located in the upper part of Gromo, toward the river Goglio and belonged to the Buccelleni family.

[28] The contest Penna d’Oro was conceived by the De Marchi sisters,[29] the lawyer Licinio Filisetti and an engineer Adolfo Ferrari with a jury represented by the poet Giacinto Gambirasio with the purpose of stimulating the literal production of literary works using the dialectal language and has been the most important cultural meeting of the village.

The hamlet of Boario Spiazzi is located on the left bank of the Serio River, nowadays almost melded with Valzella, thanks to the recent construction of some houses of blocks.

Boario is the originally bigger nucleus with its Baroque church and the nearby parish priest's house and other buildings made of rocks and slate roofs.