More than 40 per cent of the A-level marks awarded to Hertfordshire students were worth A or A* grades in 2022, according to Ofqual statistics.
On results day last week (Thursday, August 25), 42.3 per cent of the grades which A-level students received in the county were listed as A or higher.
Their achievements mean pupils in Hertfordshire are some of the highest achievers in England - fifth in Ofqual's national A or A* table.
Ahead of Hertfordshire's learners were cohorts in Oxfordshire (42.7pc), Buckinghamshire (44.2pc), Surrey (44.5pc), and - at the top of the table with 53.6pc - Rutland.
There were only two other counties where more than 40pc of the marks awarded were worth A or A* grades - East Sussex (41.3pc) and Cambridgeshire (41.1pc).
On results day, Councillor Terry Douris, who is responsible for education at Hertfordshire County Council, said he wanted to congratulate students on their achievements.
Cllr Douris said: "I was at Broxbourne in the morning where there was a high level of excitement.
"I then went to Hemel Hempstead where students, teachers and parents were very pleased."
He added: "For the next year, I think we will focus on what we always do, which is getting the very best education provision - to make sure that when Ofsted come, the schools are prepared to achieve the highest ratings."
Headteachers throughout Hertfordshire congratulated their students on results day, sharing messages of delight with pupils and parents.
Liz Ellis, headteacher at Fearnhill School in Letchworth, said: "Like all young people across the country, they have faced the challenge of learning through the pandemic in very difficult circumstances.
"They have shown determination, commitment and sheer grit to succeed as they have today.
"Their work and the support of their teachers, families and community have been rewarded with excellent results, ensuring they can all move to their next step with confidence and pride."
At Stanborough School in Welwyn Garden City, 40pc of grades received were either A or A*.
Merry John, headteacher, said: "Our children who are at the heart of everything we do are more than just grades.
"Grades do not define them but their character does. I am so proud of each and every one of our Year 13 students.
"The last time our students were in full-time education was in Year 10. They had been significantly impacted by COVID-19, were not able to end Year 11 like previous students, were not able to have a Year 11 prom and did not get the chance to sit their GCSE examinations.
"In spite of all this, the resilience, strength of character, fighting spirit and the dedication they have demonstrated has been remarkable."
In addition to A or A* results, 99.2pc of the A-level grades received by students in Hertfordshire were listed as E or above.
Nationwide, the same figure stood at 98.6pc.
Alongside the counties where pupils received the highest number of A or A* results in the county, Ofqual has listed the counties in England where fewer than 30pc of students received A or A* grades.
Among them is Bedfordshire, which sits next to Hertfordshire, where 27.4pc of grades received were A or A*.
Bedfordshire also fell below the England average for pass grades, with 97.3pc of grades awarded at E or above.
The counties with the lowest percentages of A or A* grades in England were: Northamptonshire (29.7pc), Merseyside (29.5pc), Cumbria and Leicestershire (29pc), Staffordshire (28.4pc), Suffolk (28.2pc), Bedfordshire (27.4pc) and Isle of Wight (24.3pc).
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