Treynor is a city in Pottawattamie County, Iowa, United States. The population was 1,032 as of the 2020 census.

Pottawattamie County is a county located in the U.S. state of Iowa. At the 2020 census, the population was 93,667, making it the tenth-most populous county in Iowa. The county takes its name from the Potawatomi Native American tribe. The county seat is Council Bluffs.