The A390 is a road in Cornwall and Devon, England. It runs from Tavistock to 5 miles (8.0 km) north west of the city of Truro. Starting in Tavistock, it heads south-westwards towards Liskeard, crossing over the River Tamar and into Cornwall, then through Gunnislake and Callington. Immediately before Liskeard, it merges with the A38 north of the town. It diverges from the A38 at Dobwalls, where it then runs in a south-westerly direction to Truro via Lostwithiel, St. Blazey, and St Austell. It then forms an upside down elongated square loop, and bypasses Truro City Centre. It then heads north west out of the city, where it forms the main corridor into Truro from the west. It passes the Royal Cornwall Hospital and skirts the village of Threemilestone, before linking up with the A30 road at Ch