Esthwaite Water, the Lake District's largest privately-owned lake, is the first lake in the world to be sold on the internet auction site.
Owner Nigel Woodhouse is approaching retirement age and is selling the 280-acre lake and its established leisure businesses.
Mr Woodhouse, who has been in charge of the lake for 32 years, told The Westmorland Gazette he chose eBay because he wanted to "broadcast it to the world".
"The literary and natural importance of the lake is likely to attract an international audience so what better way to get the message out?"
He added: "I will be sad to see it go - it has been my life."
Esthwaite Water, which straddles the villages of Near Sawrey and Hawkshead, was described by author Potter as her "favourite lake" and the area now pays homage to the Peter Rabbit creator in the form of a licensed nature trail.
It also features in the Lyrical Ballads of poet Wordsworth.
The lake has a classified ad price on eBay of £300,000.
The seller notes state: "A significant 280-acre lake in the heart of the Lake District with well-established leisure businesses offering a shop, cafe, boating, fishing, and visitor attraction. Once- in-a-lifetime opportunity to acquire an assignable lease on the largest privately owned lake in the Lake District.