From Roma:

take the E80 highway Rome-Civitavecchia and follow the signs for Grosseto. After 5 km, before arriving at Tarquinia, turn right for Monte Romano/Viterbo. At the roundabout take the exit for Loc.Montericcio. Follow 5 km and have arrived at the gate.

From Viterbo:

drive along the highway Orte-Civitavecchia until Vetralla, go to Monte Romano and continue to Tarquinia. Do not enter to Tarquinia but go straight to the roundabout and take the exit for Loc.Montericcio. Follow 5 km and you have arrived at the gate.

From Grosseto:

take the E80 to Rome. Do not enter to Tarquinia, follow the signs for Rome-Civitavecchia. Immediately after the bridge, take the ramp on the right for Monte Romano/Viterbo. At the roundabout take the exit for Loc.Montericcio. Follow 5 km and have arrived at the gate.