By 1800, cloth was heading the same way as tin had done a century earlier, but copper was starting to be seriously mined in the area, to such an extent that by 1817 the Tavistock Canal had been dug (most of the labour being done by French prisoners of war from the Napoleonic Wars to carry copper to Morwelhlam Quay on the river Tamar , where it could be loaded into sailing ships weighing up to 200 tonnes. In 1822 the old fairs were abolished in favour of six fairs on the second Wednesday in May, July, September, October, November and December.
In the mid-nineteenth century, with nearby Devon Great Consols mine at Blanchdown one of the biggest copper mining operations in the world, Tavistock was booming againreputedly earning the 7th Duke of Bedford alone over £2,000,000. A statue in copper of the 7th Duke stands in Guildhall Square. The Duke built a 50,000 imperial Gallon (230 m3) reservoir to supply the town in 1845, as well as a hundred miners' houses at the southern end of town, between 1845 and 1855. There is a strong, recognisable vernacular Bedford style of design, exemplified most strikingly in Tavistock's Town Hall and "Bedford Cottages" ubiquitous across Tavistock and much of the local area to the north and west, where the Bedfords had their estate and summer "cottage" at Endsleigh House and Gardens, which since 2005 is the Hotel Endsleigh run by Alex Polizzi.
Tavistock was deprived of one member of Parliament in 1867 and finally disenfranchised in 1885. The railway came to the town in 1859, with the town being connected to the Great Western Railway and the London and South Western Railway. At around this time the centre of town was substantially and ruthlessly remodelled by the 7th Duke of Bedford, including the construction of the current Town Hall and Pannier Market buildings , and the widening of the Abbey Bridge, first built in 1764, and a new Drake Road ramped up northwards from Bedford square to the LSWR Station.Tavistock (North) Railway Station opened to much acclaim and fanfare in 1890. The population had peaked at around 9,000. By 1901 the population had halved, recorded as 4,728. In 1968, following the Beeching Report Tavistock Station closed its doors, and in 1999 English Heritage listed the building as Grade II.
In 1911, the Bedford influence on the town came to an end after over 450 years, when the family sold most of their holdings in the area to meet death duties. The Bedford name can still be seen in many place names around the town. The Town Council is the owner of much former Bedford Property from around this time, making it one of the richest parish councils in England.
West Devon Borough Council is based in Tavistock, about 500 metres north of Bedford Square at Kilworthy Park. There is a small police station under part of the Bedford building complex on Bedford Square but the adjacent historic Magistrates Court has been closed and the nearest criminal court is now at Plymouth.
Tavistock had two railway stations, both now closed. Tavistock South was the Great Western Railway Station on the route between Launceston and Plymouth. This was closed and mostly dismantled between 1962 and 1965. The station was sited to the south of Bedford Square, just over the bridge and to the right—now a council depot: no trace of the station remains
Tavistock North was the Plymouth, Devonport and South Western Junction Railway's station, operated by the London and South Western Railway, on the route between Lydford and Plymouth via Bere Alston. This opened on 2 June 1890 and closed on 6 May 1968. The main station building survives as railway-themed bed and breakfast accommodation while the extensive goods yard is now known as Kilworthy Park and houses the offices of West Devon Borough Council. The railway for around a mile south of Tavistock North station is open to the public as a footpath and nature reserve and it is possible to walk across the viaducts that overlook the town.
In 1986, the town's two newspapers, the Tavistock Gazette (founded in 1857) and the Tavistock Times (established in 1920) merged to form the current weekly publication, the Tavistock Time Gazette, with a circulation of around 8,000 The newspaper is owned by Tindle Newspaper Group. The newspaper celebrated its 150th anniversary in 2007, with a visit from the Prince Of Wales and Duchess Of Cornwall.
In July 2006 Tavistock was named the eastern Gateway to the Cornish Mining World Heritage Site, which runs westward through the Tamar Valley and Great Consols Mine, down the spine of Cornwall to Lands End. This £75 million project is likely to bring more tourists to Tavistock. A £1.1million World Heritage Site Interpretation Centre, planned for 2007, to be built in the area of the Guildhall, and overlooking the River Tavy has not been achieved.