Wisconsin’s Lake Chippewa is home to a giant drifting island that locals frequently need to move around using their boats.

The island needs to be shifted on a near-annual basis so it doesn’t float too close to a bridge that offers passage between the east and west sides of the lake. 

Incredible video footage of the ritual, which happens almost every year, shows locals in their boats working in unison to push the island away from the bridge. 

It’s one of several floating islands on the lake, which was created in 1923 after a dam was built on the Chippewa River and flooded 15,000 acres (6,070 hectares) of land, Discover Wisconsin reveals. 

The lake’s unique floating islands began as chunks of peat bog that rose up from the land beneath the lake. Over time vegetation started to grow on these ‘islands’ of bog and soon an entire ecosystem began to thrive. 

Wisconsin’s Lake Chippewa is home to a giant drifting island that locals frequently need to move around using their boats 

The island needs to be shifted on a near-annual basis so it doesn’t float too close to a bridge that offers passage between the east and west sides of the lake 

Since the lake – which is also known as the Chippewa Flowage – was formed, some of the biggest floating bogs have broken apart into smaller islands before eventually disappearing. 

The floating bog island that’s proving troublesome for locals is known as the ‘Forty Acre Bog’ and is crowned by tamarack larch trees. 

Last year, it took over 20 boats to come together to push the island away from the bridge. 

Above is a still from incredible video footage of the island-moving ritual, which happens almost every year 

The lake’s floating islands began as chunks of peat bog that rose up from the land beneath the lake, which was created in 1923 after a dam was built on the Chippewa River and flooded 15,000 acres (6,070 hectares) of land

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Denny Reyes, a nearby resident and owner of The Landing Restaurant and Resort told Northern News Now: ‘It’s one of the first things you look for when you come in here in the morning: Where’s the bog?’ 

Greg Kopke, a local homeowner, told the publication that the bog doesn’t always move, but when it does it has to be driven into the ‘right spot’.

The Lake Chippewa Flowage website notes that even though the lake was formed a century ago, ‘new bogs can be created anytime’. 

It says: ‘A phenomenon known as “mud bogs” can appear at any time, although they show up most frequently in the fall. 

The floating bog island that’s proving troublesome for locals is known as the ‘Forty Acre Bog’ and is crowned by tamarack larch trees 

Last year, it took over 20 boats to come together to push the island away from the bridge 

‘They will either rise to the surface temporarily and then slowly sink down to the bottom again, or they may stay permanently on the surface and eventually develop plants and trees.’

It adds: ‘[The islands] can range in size from the size of a parking space to several acres.’ 

To keep tabs on the Forty Acre Bog’s whereabouts, the Facebook group Lake Chippewa Flowage Resort Association was set up. 

Visitors to the spot may observe animals from black bears to deer and otters, with the creatures protected by local wildlife authorities.

And the lake is filled with attractions, proving popular for fishing trips, boat days and wild swimming.