1904 postcard showing the south half of the Monadnock Building. The building was constructed in two parts for Boston developers Peter C. and Shepherd Brooks along the west side of Dearborn Street, between Jackson Boulevard and Van Buren Street. The north half, facing Jackson, was designed by Burnham & Root in 1889 and completed two years later. It is notable for its load bearing masonry walls, the tallest building ever constructed in this manner. It was also briefly the world’s tallest office building.
The south half, facing Van Buren, was completed in 1893 from designs by Holabird & Roche and comprises a steel frame clad in purple-brown brick and terra cotta, and capped with a copper cornice. It is actually two buildings, designated as the Katahdin and the Wachusett. The Katahdin, built adjacent to the north building, used a similar iron framed method of masonry construction, whereas the Wachusett was entirely steel framed. The total cost was $2.5 million (more than $80 million today).
When completed, the Monadnock was the largest office building in the world, with 1,200 rooms and an occupancy of over 6,000. It functioned as its own postal district with four full-time carriers delivering mail six times a day, six days a week. The construction methods employed from north to south, are a stunning example of the rapid transformation from masonry to steel frame construction during this time period.
The building was designated a Chicago landmark in 1973.