NottinghamPost.com, part of Local World, received an average of just over 1 million unique monthly browsers, based on figures for the second half of 2013 – an increase of 54.1 per cent on January to June, and growth of 81.3 per cent year-on-year.
Part of the reason for the leap in traffic was the Nottingham Post securing its first "proper viral story" – about a man who spent £450 on a photograph of an XBox One – in December, said Nick White, head of insight at Local World.
"It was published as a straight-forward news story, but it got picked up very quickly on Facebook and Twitter," he explained.
The story picked up 63,000 'likes' on Facebook and was linked to by 1,600 "quite hefty" sites including YouTube and Huffington Post, he said, resulting in 1.6 million unique browsers. The website received just under 2.6 million unique browsers for the month in total.
"What we like about this story is that we didn't chase the audience on this, the audience came to us," White added.
However, he also cited the increase in traffic to the Nottingham Post's website as being a result of the wider Local World strategy, which he said had seen a more "aggressive" focus on search engine optimisation (SEO) and social media.
"It was a bonus at the end of a year in which a strategy was put in place and executed with great success," he added.
Other notable increases include Trinity Mirror's GazetteLive.co.uk (up 51.8 per cent) and Birmingham Mail (up 51.5 per cent), as well as KM Group's Kent Online (up 43.4 per cent).
Of the six local news groups audited by the Audit Bureau of Circulation (ABC), KM Group saw the biggest increase in monthly unique browsers (43.4 per cent) and a growth of 93.9 per cent year-on-year.
The outlet has one main website, Kent Online, which carries content from its portfolio of titles across the county. KM Group had the lowest total unique browsers reported by ABC, with an average of 914,200 uniques.
Local World, which was only founded in January 2013, recorded an average of 11.7 million monthly uniques in the last six months of the year, up 35.1 per cent on the first six months.
Midland News Association, which owns the Express and Star and the Shropshire Star, was up 25.1 per cent with an average of just under 2 million uniques.
Elsewhere Johnston Press recorded 13.1 million uniques (up 17.9 per cent) while Newsquest reported 12.9 million uniques - an increase of 19 per cent on the first six months of the year.
ABC defines a unique browser as any visit to a website from a computer or a mobile phone. The average daily figures for each regional newspaper group are shown in the graph below.
Additional reporting by Rachel Bartlett