Alden is a city in Hardin County, Iowa. Its population at the 2000 census was 904.
It is the smallest town in the United States to have an endowed Carnegie Library. It was built at a cost of $9,000. It was a gift from Andrew Carnegie on November 7, 1913. The Library is a part of the National Register for Historic Places from 1966.
The city population predominantly comprises White Americans. A sizeable percentage of the population are people of Hispanic origin.