[2] Organized at a time of tensions before the Civil War, the county was named in 1853 for the union that people wanted to preserve.

Settlers used Pisgah as a base to establish farms along the Grand and Platte rivers that run through the county.

They found a market for their produce with the emigrants traveling overland to California to take part in the Gold Rush.

In 1851 one settler counted 2,600 teams driven by emigrants to California; they often drove herds of sheep and cattle, trying to get animals to the gold fields to feed the miners, but many died along the way.

The county was named for the union which many people wanted to preserve, at a time of rising tensions between the North and the South.

[4] After the American Civil War, railroad construction linked the areas of the county, giving rise to new towns, and gave access to other markets.

In 1868 the railroad reached Afton, Iowa, and the next year Creston, the county seat, was made a division point.

The Burlington Northern Santa Fe Railroad (BNSF) continues to be important in the area, serving as the chief network for hauling grain and coal.

It held exhibits of farm products and resource commodities from counties of the association, including wood, coal, sandstone, and marble.

The palace was such a success that the Bluegrass Association commissioned a larger one the following year, which supplied about three times as much space.

The county is now safely Republican, as Donald Trump won it in 2020 with nearly 65% of the vote and a margin of victory of nearly 32%, turning in the best performance and margin of victory for a candidate of any party since Dwight D. Eisenhower won the county in 1952 during his nationwide landslide.