National Register of Historic Places in Humboldt County
The French Empire Mansard Building was constructed by James Simpson, a well known builder who constructed several other large buildings, in 1883 to house the new lodge hall for the Independent Order of Odd Fellows.
The large two story building was constructed of brick with an imposing two story entrance pavilion bordered by specially formed iron columns.
This is Eureka's finest example of Second Empire architecture.
Excerpted from the NRHP Nomination.

The Independent Order of Odd Fellows (I.O.O.F.) is an altruistic fraternal organization derived from the similar English Oddfellows service organizations which came into being during the 1700s....Although in Britain the Odd Fellows tended to meet in pubs, in the U.S. the lodges often built their own facilities. Many of these are now on the U.S. National Register of Historic Places....
From Wikipedia entry for Independent Order of Odd Fellows
Historic IOOF Buildings in California
Arbuckle, Arroyo Grande, Big Oak Flat, Colusa, Copperopolis (1874-1903), Copperopolis (1903-1939), Coulterville, Etna, Eureka, Farmington, Ferndale, Forest Hill, Galt, Georgetown, Geyserville, Hanford, Jenny Lind, Knights Ferry, La Grange, Live Oak, Mokelumne Hill, Murphys, Nevada City, Oakdale, Orland, Point Arena, Quincy, Red Bluff, Roseville, Sebastopol, Snelling, Truckee, Wheatland, Woodbridge, Woodland, Yreka
Historic IOOF Buildings in Nevada
Austin, Gardnerville, Nevada, Yerington
Historic IOOF Buildings in Oregon
Ashland, Coquille, Gold Hill, Klamath Falls
Historic IOOF Buildings in Utah