The news was welcomed by Andrew Fox, chair of Visit Northumberland, who said tourist numbers had been growing steadily in recent years.
He added: “It’s great to see holiday cottage demand and yield thrive in so many different areas of Northumberland which reflects the growing interest in the amazing attractions, places, and experiences available in the county.
“Northumberland provides a great opportunity for property owners whether they are based on our stunning coastline, within our tranquil landscapes or in the heart of our traditional towns and villages.”
Overall income was highest in Grasmere, Cumbria, where holiday let owners made £43,100 a year in 2023.
In Ambleside, just north of Windermere, the average income was £32,900 a year, the analysis showed.
Sykes’ data showed the average income for a British holiday let owner is £24,500. A quarter of holiday let owners use their property to generate income during retirement, the agency said.