Tens of thousands of patients were waiting for routine treatment at the Royal Devon University Healthcare Foundation Trust in September, figures show.
One organisation has suggested winter pressures on the NHS are already kicking in.
NHS England figures show 79,020 patients were waiting for non-urgent elective operations or treatment at Royal Devon University Healthcare NHS Foundation Trust at the end of September – down slightly from 79,110 in August, and 81,737 in September 2022.
Of those, 5,420 (7%) had been waiting for longer than a year.
The median waiting time from referral at an NHS Trust to treatment at the Royal Devon University Healthcare Foundation Trust was 16 weeks at the end of September – the same as in August.
Nationally, 7.7 million people were waiting to start treatment at the end of September.
Professor Vivien Lees, from the Royal College of Surgeons of England, said: “Winter pressures have already started to affect the system.
“We are concerned that with increased demand, record staff vacancies and industrial action, this will all continue to hold back recovery efforts.”
Separate figures show 1.6 million patients in England were waiting for a key diagnostic test in September – the same as in August.
At the Royal Devon University Healthcare Foundation Trust, 16,369 patients were waiting for one of 13 standard tests, such as an MRI scan, non-obstetric ultrasound or gastroscopy at this time.
Of them, 6,690 (41%) had been waiting for at least six weeks.
Other figures show cancer patients at the Royal Devon University Healthcare Foundation Trust are not being seen quickly enough.
The NHS states 85% of cancer patients urgently referred by a GP should start treatment within 62 days.
But NHS England data shows just 67% of patients urgently referred by the NHS who received cancer treatment at the Royal Devon University Healthcare Foundation Trust in September began treatment within two months of their referral.
That was down from 69% in August, but up from 59% in September 2022.
Recent projections by the Health Foundation suggest waiting lists will top eight million patients next year, regardless of whether industrial action continues this winter.
Strikes by health workers have been blamed by politicians for contributing to these waiting lists – but the charity's analysis suggests they are responsible for just 3% of the current waiting list.
Despite the significant challenges faced by the NHS, the Health Foundation said it was possible to clear the backlog – although it will require "sustained focus, policy action and investment".
Professor Sir Stephen Powis, NHS national medical director, said the NHS was making progress despite pressures on the service, such as industrial action.
He said: "It is important to recognise the incredible efforts of staff who are seeing and treating many more people than pre-pandemic – delivering record numbers of diagnostic tests and checks, treating more people for cancer at an earlier stage, and completing thousands more routine procedures."
He urged members of the public to get flu and coronavirus vaccinations if they are eligible.