Mosquito Pass Preserve

Henry Island

Year Protected: 2003, 2005, 2007

Land Protected: 55.8 acres

Shoreline Protected: 4,100 feet

On June 1, 2003, The San Juan Preservation Trust, with significant financial support from the San Juan County Land Bank, completed a $950,000 land conservation purchase that permanently protected the extensive tidal salt marsh isthmus on Henry Island, a dramatic and ecologically-unique San Juan Islands landmark.

The acquisition included two inter-related components: The outright purchase of a 21-acre meadow, marine shoreline and forested upland, and the purchase of a 21-acre conservation easement – in the form of an option to be executed in 2005 – on the adjoining 21-acre salt marsh isthmus. With the subsequent addition of a conservation easement donation on another adjacent property, this combination of land conservation methods have created almost 56 acres of exceptional open-space and wildlife habitat that have been permanently protected.

The isthmus, which forms the crossbar of the distinctive “H” shape of Henry Island, is home to an abundance of wildlife and native plant communities. The property is bounded on the north by Nelson Bay, on the east by Mosquito Pass, and on the south by Open Bay – three bodies of water providing 4,100 feet of marine shoreline.

There had been longstanding local and state interest in preservation of the Henry Island isthmus. As a natural system, the area displays both high quality and high diversity, including a shallow mud-bottomed bay, inter-tidal zone, coastal beaches, salt-grass meadow, natural dunes, and dry coniferous forest. The rare accretion beach is described in the 1999 Priority Habitat Assessment for San Juan County as one of the most important sites of this type in Washington State. A natural area assessment conducted by The Nature Conservancy identified the area as “highest priority” for conservation, and described the salt marsh and mud flats on Open Bay and Nelson Bay as “probably the finest examples of their kind in San Juan County.”

Henry Island Enclave, LLC purchased the property in 1999 and was preparing to divide it into smaller residential lots. A plan to build a 300-foot dock to support these smaller lots had received preliminary staff approval from the San Juan County Planning Department and was awaiting final approval from a hearing examiner in March of 2003 when the Preservation Trust stepped in to protect the property.

Utilizing an early commitment of $475,000 from the San Juan County Land Bank and two significant lead gifts from concerned Henry Island families, The Preservation Trust staff assembled a steering committee and undertook an aggressive community campaign. Despite a challenging economy and an accelerated time schedule, the remaining funds were raised from private donors in less than four months. Most of this private money came from the friends and families of Henry Islanders, supplemented by additional support from generous Preservation Trust members.

Dennis Shaffer, Director of the Land Bank at the time of the Mosquito Pass Preserve acquisition, expressed his excitement over the potential of this partnership for future land conservation transactions in the San Juans. “The Land Bank and The Preservation Trust are becoming a significant conservation force in our islands by leveraging public and private financial resources. Bringing these two successful land conservation organizations together for projects like the Henry Island Isthmus greatly enhances our ability to preserve the most special places in the San Juan Islands.”

The Henry Isthmus/Mosquito Pass Preserve is open to the public. Click here for visitor information and trail map.