Holt County, Missouri: History
The original area of Holt County was much larger than its present area. When it was first organized it comprised the current Holt County boundary, all of Atchison County, that part of Nodaway County west of the Nodaway River, and the aforementioned claim extended ten miles north into southwestern Iowa; an area more than 1,350 square miles in all.
The first Post Office in Holt County opened in 1839 and was located on Thorp's Creek near Oregon. It was known as Thorp's Mill and closed in 1841.
In 1972, the Holt County Historical Society was established.
Holt County was impacted by the 2019 Midwestern U.S. floods. About 30,000 acres (12,000 hectares) of the 95,000 acres (38,000 hectares) that flooded in spring 2019 were still underwater in late October. Some of the floodwater was expected to freeze in place over the winter.