Miss B. Haven and the Monkey Island Denver Ghost Story

Reviewed by Josh N · Updated August 13, 2026 · How we verify

Almost nobody sets foot on it any more, which is part of why the Monkey Island Denver ghost story has lasted. The island itself is a modest lump of ground in Grasmere Lake, inside Washington Park on the south side of Denver, Colorado, and it has been there since the man-made lake was dug and filled in 1906. What it did not have for the first sixty years was a name.

Quick orientation: a small island in Grasmere Lake, Washington Park, Denver. No bridge, no legal way across, best viewed from the shore path. The legend attached to it names one person, Beatrice Haven, and one detail that does the work of a punchline: the birds.

How a Patch of Dirt in Grasmere Lake Became Monkey Island

The island earned its nickname in the 1960s, when it became what one description calls a lentic lovers’ lane, punctuated by the recreational drug use common to the era. Locals described it as an island for monkey business, and the name Monkey Island stuck. That is the whole etymology, and it is worth stating plainly, because ghost stories tend to grow more elaborate origins than the truth requires.

The Bridge Came Down in the 1970s

The island was once connected to the shore. The bridge was removed in the 1970s specifically to discourage the behaviour that had given the place its name. In the 2000s a second, less deliberate deterrent arrived: the water source for the lake was switched from the Platte River to recycled wastewater. That water carries high concentrations of nitrogen and phosphorus, and the result has been an abundance of algal blooms in the water surrounding the island, where Platte River water had historically left the lake looking cleaner. Efforts began in 2011 to improve the lake’s overall water quality.

None of that is paranormal. It is, however, the practical reason the island now reads as off limits and slightly unwelcoming, which is fertile ground for a story.

Miss B. Haven, and What the Legend Actually Claims

Local legend holds that a habitue of the island in the 1960s, Beatrice Haven, known as Miss B. Haven, died unexpectedly in her twenties and has haunted the place since. The pun in the name is not subtle, and it is the strongest signal that this is folklore rather than documented history. No record of her life or death appears in the source material for this island, and nobody should present her as a verified person on the strength of the tale alone.

What the Story Says Happens Late at Night

As the story goes, she appears late at night to boys who venture onto the island. The encounter ends when the squawking of the island’s birds, including the night herons that currently inhabit it, causes her to disappear. That is the reported shape of the phenomenon in full: a night-time apparition, a specific type of witness, and a bird call that dismisses her. It is a tidy piece of storytelling, and the night herons are real residents of the island, which gives the legend a hook in something a visitor can genuinely hear after dark.

Looking at Monkey Island From the Washington Park Shore

Washington Park is public ground and the shoreline of Grasmere Lake is easy walking. The island is not reachable: the bridge has been gone since the 1970s, and the algal blooms in the surrounding water are reason enough not to attempt a crossing. Treat this one as a lakeside curiosity rather than an investigation site. Bring binoculars for the herons, which are the most reliably observable thing about the place.

Address: Grasmere Lake, Washington Park, Denver, Colorado

See Monkey Island for Yourself

Sources

• Washington Park Master Plan 2011
• Library of Congress Catalog (Loc (official))
• GeoHack – Monkey Island
• Wikipedia: Monkey Island (Denver)

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