| Polygonal Barn, Lincoln Township | |
| Coordinates: | 41.5878°N -91.3947°W |
| Area: | less than one acre |
| Built: | 1880 |
| Builder: | George Frank Longerbean |
| Added: | June 30, 1986 |
| Refnum: | 86001452 |
The Polygonal Barn, Lincoln Township was a historic building located in Lincoln Township in rural Johnson County, Iowa, United States. It was built in 1880 by George Frank Longerbean. The barn was an 8-sided structure and has subsequently been torn down.[1] It featured a bell shaped roof of curving hand-laminated beams.[2] The building was listed on the National Register of Historic Places in 1986.