The circuit starts from the lower viewpoint (belvedere inferiore) of the Marmore Waterfalls. It joins the SS Valnerina (state highway) and goes along a flat stretch as far as a roundabout. Right turn towards Arrone and, once over the bridge of the Nera river, it passes through the village. Carrying on past a crossroads and always straight on in direction Piediluco. Here the first upward slope begins. It is called Forca d’Arrone, famous because the Tour of Italy has often passed here. Once on top there is a magnificent view, then downwards towards Piediluco Lake. At the bottom of the slope, right at the crossroads and shortly after left towards the village of Piediluco, it goes right through this village and comes out once again, after passing a canal, onto the country road, taking a left towards Terni. The circuit is flat as far as the village of Marmore (where it is possible to visit the higher viewpoint of the Waterfall) and after a few bends it starts downwards towards Terni. Arriving at a large roundabout it proceeds straight along a wide avenue and, after having gone past a crossroads with traffic lights, it carries straight alongside a public park as far as a roundabout. Then right and, shortly afterwards, left at the traffic lights and left again taking the road that goes running along the basilica of St. Valentine and carries on to Stroncone. This part is slightly upward and once having passed a bridge on the right becomes steeper as far as the village centre. From here it goes down with two hairpin bends to then go left towards Coppe and, shortly afterwards, right towards Vascigliano. This part goes steeply downward, passes through the village of Colmartino as far as a crossroads where it turns right. Then there is a flat part, at the first junction, left turn towards S. Urbano. After a flat part it begins to climb up as far as Ville di Vasciano, and then, after the turn off for the Speco Francescano (Fransican sanctuary), it continues along an undulating road full of bends until Narni. Once through the town it goes down towards the Nera river and goes under the Augustus Bridge to then continue towards Stifone on a flat road. Once past the town that overlooks an artificial turquoise coloured lake, it carries on turning right towards Montoro. At first the road going up to the town is steep but then becomes softer and undulating joining the road to Amelia on the left reaching Amelia via Fornole. It enters Amelia by a side gate on a panoramic road that takes us downwards to the main gate. Then it turns right and goes along a long stretch of the ss 205 that goes to Orvieto. After Lugnano in Teverina it turns left for Alviano which it passes through shortly afterwards going downward as far as Alviano Scalo where it turns right and goes along a flat stretch running along the Alviano oasis. Staying in this direction we arrive at Baschi and shortly afterwards, a crossroads taking a right towards Corbara lake (direction Todi).
It goes past the dam and, immediately after Corbara carries on to Orvieto on an asphalted country road that goes up and down until Ciconia. It turns left and crosses the Tiber and, at the roundabout, takes the ss 71 going to Viterbo and, arriving at a junction, right turn to climb up to Orvieto. Having passed the Roman gate it enters Orvieto and goes through the historical centre until the Cathedral. Going along Corso Cavour it leaves the town walls and goes right and shortly after on the left towards Sferracavallo and left again towards Castel Viscardo. After a flat stretch the upward slope leading to the town starts. From the roundabout in direction Monterubiaglio as far as the junction (a left U bend) for the railway station of Allerona. Once here it goes right and, passing under the railway track takes the road for Ficulle. A long upward slope starts ending at the crossroads with the SS 71. It goes left and after Ficulle goes down towards Fabro Scalo. At the roundabout it goes straight on towards Monteleone di Orvieto which is reached after a flat stretch and a long upward slope. Having arrived at the town, at the roundabout, it turns right towards Perugia and immediately right again towards Montegabbione. It goes through the small town and proceeds along a very undulated road with short but steep upward slopes until the crossroads with the SP 57. It then goes right and the upward climb to Monte Peglia begins. After the antennas it goes down towards Orvieto and at Colonnetta di Prodo takes a left turn towards Fossatello and then Corbara. At Corbara it goes left towards the dam, after passing the dam it goes left towards Todi.
It follows the lake for a stretch until reaching the right turn for Civitella del Lago. Here a long upward climb starts that finishes a few kilometres after the town and joins the SP 34. It takes a left turn and after a downhill stretch turns right (U bend) towards Melezzole. This is an undulated stretch and having passed Toscolano starts downhill until dell’Aquila. It carries on for Avigliano Umbro and, after having touched the village of Dunarobba, at the junction, it goes right for Montecastrilli. It goes through the town and proceeds in the direction of Casteltodino. Here it goes left and goes downhill towards Acquasparta and passes through the town as far as the crossroads with via Tiberina where it goes right towards San Gemini. After a short flat stretch it heads left passing under the E 45 and continues towards Cesi. After a short slight slope the climb up to the Archaeological Park of Carsulae starts followed by a few kilometres to the turnoff for San Gemini. It goes right and proceeds down to the water mineral springs. Here we join via Tiberina once again which goes on a downhill stretch as far as San Gemini and then, past the village, after a wide bend, turns left towards Terni. The downwards slope continues until the industrial zone of San Gemini. Take the road on the left to Collestacio going up as far as the turn-off then go right for ‘strada di Vagoti’. On the left go under the underpass and join the ‘strada di Mazzamorello’ on the right and carry on until the station of Cesi, go past and take ‘strada della Pittura’ on the left. This is the last challenging part. Having reached the top it follows the large walls and comes out onto SP 22 and turns right towards Terni. It goes slightly downhill and then left towards Terni along a by-road running alongside the railway track. It goes through Terni and takes the SS Valnerina and after 7 km. returns to the Marmore Waterfalls. A journey of 317 km.