Royal Cornwall Hospitals NHS Trust was caring for 55 coronavirus patients in hospital as of Tuesday, figures show.
NHS England data shows the number of people being treated in hospital for Covid-19 by 8am on September 21 was up from seven on the same day the previous week.
The number of beds at Royal Cornwall Hospitals NHS Trust occupied by people who tested positive for Covid-19 more than tripled in the last four weeks – 28 days ago, there were 15.
Across England there were 5,142 people in hospital with Covid as of September 21, with 145 of them in mechanical ventilation beds.
The number of Covid-19 patients hospitalised nationally has decreased by 18% in the last four weeks, while the number on mechanical ventilators has decreased by 3%.
The figures also show that 62 new Covid patients were admitted to hospital in Royal Cornwall Hospitals NHS Trust in the week to September 19. This was up from 17 in the previous seven days.