40-Mile Loop

[4] As part of beautification planning for the Lewis and Clark Centennial Exposition of 1905, Portland's recently established Parks Board invited the Olmsted Brothers in 1903.

In 1912, another city planner, Edward H. Bennett, also recommended developing a ridgetop park long the West Hills.

However, shortly afterward, most of the lots sold in Forest Park forfeited to the city or Multnomah County due to high assessments for road building, and a landslide.

[3] Little more happened until 1978: at the request of Oregon legislators, U.S. Congress stripped the Columbia Slough of its "navigable" status, enabling the land to be dedicated to recreational use, an important component of the Olmsted plan.

The Oregon director of the Nature Conservancy responded to withering federal funds for parks and natural areas by reviving the loop plan to enthusiastic receptions by the City, suburban cities, federal agencies, conservationists, and civic groups.

[4] The trail has a variety of sections: some are on level ground, such as along the Columbia River; others are heavily forested and/or mountainous, as through Washington Park's Hoyt Arboretum.