I used to pass this somewhat decrepit octagon house in Monroe --- along Highway 14 between Knoxville and Newton --- about once a month when driving from Chariton to Mason City and wish now that I'd stopped a little longer to take more photos. No idea how it's doing, but this was the way it looked during September of 2008 --- when elections were in the offing.
The house reportedly was built by pioneer attorney Jacob Kipp during the 1860s, perhaps not long after the Civil War had ended. It is constructed of brick, covered some time after the mid-1930s by stucco.
I'm only bringing it up now because I happened upon Ellen Puerzer's and Robert Kline's Octagon House Inventory Web site the other day, an attempt to account for all of the octagon houses still standing --- and many that aren't --- in the United States. Click on the link to go there, then scroll down and hit "Iowa" to find more information about the 33 octagons the pair have located in Iowa (a few round and at least one hexagonal houses are included).
There are many theories about why people built octagon houses. But Orson Fowler, a phrenologist and social activists with a bit of the huckster built in for good measure --- no architectural training, however --- popularized them with a book, "The Octagon House: A Home for All," published in 1848.
The most elaborate octagon I've visited is Dr. Haller Nutt's "Longwood," or "Nutt's Folly," commenced in Natchez, Mississippi, just before the Civil War but because of the war and Nutt's death left incomplete (other than nine finely finished rooms on the raised basement level). It now is owned by the Pilgrimage Garden Club and operates as a museum.
The most elaborate octagon remaining in Iowa --- which I've only driven by --- is the fine Langworthy house in Dubuque, built in 1856 for Edward Langworthy.
Lineville's Gammell House used to be the octagon closest to home and I can recall driving by it alongside Highway 65 many times while headed into the wilds of northern Missouri. It has long since been torn down, but had it survived might be considered quite the architectural treasure. You'll find a photograph of it on the inventory Web site where for some reason it is described as "massive." It was hardly that.
There's also an elongated octagon located in the northeast part of Powersville, a tiny town due south of Corydon just over the line into Missouri. Just checked Google "Map" and it's still there.
Anyhow, if you're worn down by holiday preparations and interested in old houses, take a break and spend some time browsing the Octagon House Inventory site.