The fair's main entrance was at 26th and Upshur, now the site of a 1920s-era building. (The amazingly unchanged Fairmount apartment building at this intersection was built to house workers for the fair and then became a hotel for fairgoers.)
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The carriage entrance was at 28th and Thurman.
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Oregon's exhibits at the fair were housed in the Forestry Building, the world's largest log cabin, which was designed to show the world the immense bounties of Oregon's forests. The Forestry Building sat between Upshur and Vaughn at 28th, where the Old Forestry Condominiums now sit.
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The landmark Montgomery Park building at 28th and Vaughn (a former Montgomery Ward distribution center and now an exhibit space and meeting hall) sits where [the Lewis and Clark Exposition's] sunken gardens used to be.
When New York City's Olmsted Brothers came to town in 1903 to help develop a system of parks, they recommended that Guilds Lake, with its backdrop of scenic mountains, be the site of the upcoming world's fair. One distinct advantage of the site over others was that the fair could be served by existing streetcar lines.
...the Lewis and Clark Exposition, opened on June 1, 1905... The fair's main entrance was at 26th and Upshur, now the site of a 1920s-era building. (The amazingly unchanged Fairmount apartment building at this intersection was built to house workers for the fair and then became a hotel for fairgoers.) The carriage entrance was at 28th and Thurman. Oregon's exhibits at the fair were housed in the Forestry Building, the world's largest log cabin, which was designed to show the world the immense bounties of Oregon's forests. The Forestry Building sat between Upshur and Vaughn at 28th, where the Old Forestry Condominiums now sit. The landmark Montgomery Park building at 28th and Vaughn (a former Montgomery Ward distribution center and now an exhibit space and meeting hall) sits where the fair's sunken gardens used to be.
The fair lasted only four and a half months, so most of the buildings, despite their grand appearances, were cheaply built, just plaster skins over wooden frames. There were exceptions, such as the timbered Forestry Building and a few conventionally built structures that still survive. One of these, the Masonic Building, is at NW 26th and Northrup. In Saint Johns, what was originally the National Cash Register Building now houses the McMenanins-owned Saint Johns Theater and Pub. The Massachusetts Building was moved to Mount Tabor to become a sanatorium but was torn down in 1940.
Once the fair was over, the Olmstead Brothers proposed that the site be converted to a public open space, with a park linking Macleay Park to the riverfront; but the fate of the fair site was sealed, literally, beginning around 1905, when Lafe Pence, a peripatetic lawyer, miner, and entrepreneur, breezed into town.
The Forestry Building, a uniquely Northwest landmark of old growth and unpeeled timbers, went into a period of neglect after the fair, intersperses with periodic spasms of civic concern. Despite not being adequately maintained, it continued to be a tourist attraction, and its park like grounds remained popular until the building burned to the ground in 1964.
What was once a sparkling showcase of the world's bounties [the Lewis & Clark Exposition] is now a very unlovely sight: barbed wire, weedy vacant lots, and prefabricated buildings are scattered along the... street.
The parades had ended, the bunting was removed, the guests had returned home. The white plaster city on the shore of Guild's Lake would be knocked down before it could rot. Portland's debut to a world audience, the Lewis and Clark Exposition of 1905 that celebrated a new era of trade on the Pacific rim, was over.
Portland was an early adopter to hosting a global event, as much transformative as promotional, along the lines of a worlds fair or international competition.
Other western cities followed. Seattle took to the stage four years later with the Alaska Pacific Exposition and again with the World's Fair of 1962. San Francisco hosted the Panama-Pacific International Exposition in 1915 and the Golden Gate International Exposition of 1939. Vancouver BC, late to the show, caught up with Expo 86 and next years 2010 Olympics.
[This article goes on to discuss Portland's 1962 Olympic bid... Interesting stuff.
https://oregonencyclopedia.org/articles/lewis_clark_exposition/