Excavations took place at the site of Forum Sempronii in two main areas:
The forum. A 10 × 5 m trench was opened a short distance from the via Flaminia and about 20 m from the Augusteum, with the aim of locating the corner of the forum piazza as seen on aerial photographs.
At a depth of 2.00/2.10 m below ground level a number of interesting structures emerged: several well-connected Furlo limestone slabs, 20 cm thick (the only complete one measured 100 × 70 cm), which probably constituted the Forum’s floor surface. The foundations of three large bases (c.1 × 1 m) were found just to the east, probably supports for the portico that bordered the piazza on at least two sides. In fact, during urbanisation work in 1985 the foundations of four more pillars similar to those found in the 2016 trench came to light to the south, beneath the asphalt of the modern via Flaminia.
Below these bases there was an earlier floor formed by rectangular limestone slabs with a first step down towards the forum area, later obliterated by the portico. The forum floor rested on a very thick layer (over 1 m) of make-up constituted by lime and cobblestones, which must have provided stability for the paving in a zone that was probably liable to swamping. Indeed, the area outside the paving rests on a dumped layer of fine sand. Further studies are continuing with the assistance of geo-morphologists.

Area of the “Porta Gallica”. A 10 × 7 m trench was opened on the eastern limit of the city, close to the city walls, identified thanks to aerial photographs and during building work in the 1960s. The aim was to uncover the remains of the eastern gate, denominated “Gallica” in a 1st century A.D. burial inscription, housed in the Archaeological Museum of Fossombrone. In fact, the gate structures were not intercepted, perhaps because the walls are not perfectly linear and in correspondence with the via Flaminia the traces visible in the aerial photographs were of no help.

However, a gravel section of the consular road was uncovered, probably inside the town, constituted by well-compacted stone chippings, stones and gravel, and a ramp with a rising to c. 1.5 m alongside the road. Therefore, this was a road “in levada”, typical of areas subject to swamping, which provided stability and facilitated water drainage. The road’s construction can be dated to the late 1st century B.C., in the full Augustan period. Therefore, it can probably be associated with the reorganisation of the entire consular road undertaken by Augustus and which foresaw the restoration of all the bridges except two, as the emperor himself wrote in the Res Gestae.

To the south of the road, an opus vittatum structure was found to the south of the gravel road. It was characterised by two east-facing corner buttresses, whose function remains to be defined.