The World’s Largest Log Cabin: The History of the Forestry Building in Portland, Oregon

Organizers of the Lewis and Clark Centennial Exposition boasted that the Forestry Building was the world’s largest log cabin, measuring 206 feet long, 102 feet wide and 72 feet high (approximately 7 stories). Its construction was said to have cost approximately $30,000 (about $935,000 today). The lumber baron Simon Benson (1851-1942) paid for most of the giant logs that comprised the building, selected from old-growth trees in Columbia County, Oregon.

Exterior view of the Lewis and Clark Exposition Forestry Building, Portland, 1905.

Architect Ion Lewis (1853-1933), of the noted Portland architectural firm of Whidden and Lewis, designed the Forestry Building for the massive log cabin. Architectural historian Henry Matthews, in his biography of the architect Kirtland K. Cutter said of the Forestry Building: “The Forestry Building at the Lewis and Clark Centennial Exposition of 1905 in Portland, Oregon, designed by Ion Lewis of Whidden and Lewis and his young assistant Albert E. Doyle, offered another precedent for rustic architecture on a grand scale. This building, described as the “world’s largest log cabin” or the “Parthenon of Oregon” had an interior “nave” of unpeeled logs forty-eight feet high. This veritable cathedral of giant trees was by far the most popular attraction of the exposition and confirmed the public taste for such architecture.”

The interior of the Forestry Building featured colonnades of 54 massive, unpeeled Douglas Fir logs. The logs supports a 2-story center aisle, cruciform in plan, lit by skylights. The building housed an exhibit highlighting the forestry industry, local flora and fauna and Native American photos and artifacts.

After the 1905 exposition, the building was purchased by the city of Portland, which for many years let it decline and decay. It was nearly lost to fire several times when embers fell on the roof, either from nearby building fires or from wood-stove embers, but quick responses by the fire department kept it going.

In the 1940s, there was talk of actually demolishing the building, which by then had turned into a safety hazard; the balconies had been built with whole logs, which had warped, making them dangerous, and the whole building was like a banquet hall for wood-destroying organisms like bark beetles and termites.

Finally, in the 1950s, the Chamber of Commerce took up a collection to restore the place. By this time, people were starting to realize it was completely irreplaceable. Old-growth timber like what had gone into its construction could still be found, but it was deeper in the forest and less uniform. Finding 52 matching trees would be prohibitively expensive if not impossible to do, and – since the logs would have to be trucked to the site rather than just floated up the river – log-handling systems would have to be engineered to prevent the bark from being scarred by logging equipment.

By the time of the state’s sesquicentennial celebration in 1959, the building was mostly restored to its former glory. It now boasted a “priceless collection of logging and lumbering exhibits, both antique and modern,” according to an Oregonian report. Also on display was another bit of history, the first sheet of commercially produced Douglas Fir plywood ever made, a product of the Autzen family’s Portland Manufacturing Company, produced in 1904.

On August 17, 1964, the Forestry Building’s caretaker locked up for the night at around 5:30. Within 45 minutes, neighbors were noticing that something was wrong. Specifically, the place was on fire, and when the fire crews arrived at around 6:15 it was clear that nothing short of direct divine intervention was going to put it out.

“There was never a hope of saving the building,” the Oregonian reported the next day. “Nothing was saved from the inside.”

Construction of the old Forestry Building, 1904.

A 1904 postcard showing the interior scene in the Forestry Building, with the central colonnade of matched old-growth fir trees.

The immense Forestry Building is shown in 1905 during the Lewis & Clark Centennial Exposition, for which it was built.

Two women sitting in the upper balcony of the Forestry Building, 1905. This image really displays how massive the support logs were.

The interior of the Forestry Building, ca. 1905.

Exhibits within the Forestry Building during the Lewis and Clark Centennial Exposition, 1905.

The interior of the Forestry Building at the Lewis and Clark Centennial Exposition, Portland, 1905.

The Forestry Building, 1907.

The interior of the Forestry Building, 1907.

The interior of the Forestry Building, 1907.

An unusually highly detailed look at the Forestry Building, ca. 1910.

The Forestry Building, 1938.

The interior of the Forestry Building, 1948.

The Forestry Building in 1956.

A photo by A.O. Biggerstaff made in the year of the Oregon Centennial, in 1959, just a few years before the catastrophic fire.

The Forestry Building in Portland, ca. 1959.

The Forestry Building as it appeared around dusk on the night of the fire, after the flames had died down a little, Portland, 1964.