London, Merseyside, Devon, Essex and Greater Manchester led the way with events, hosting more than 280 between them.
Parks charity GreenSpace is the body behind the event and chief executive Paul Bramhill said he was pleased with the success of this year’s campaign.
"It has demonstrated what parks and green spaces mean to communities," he said.
"With over half a million people visiting their local parks, the campaign seems to have really caught people’s imagination."
Hundreds of parks bodies were involved with the events which ran from 24 July to 1 August.
Highlights from across the country included Carlisle’s temporary park opened in the city’s centre for one day, just one of 30 events staged in the Cumbrian city.
Other authorities staged events including a poetry picnic, a Eurovision pop party, a rubbish robot challenge, magic of Motown and circus skills.
The week coincided with the awarding of Green Flags and enabled many parks to stage flag raising events as part of the celebrations.
Bramhill added: "The increase of Green Flag awards has also demonstrated the quality of the UK’s parks and verified the continuing need for support and investment."