Merrill is a city in Plymouth County, Iowa, United States, along the Floyd River. The population was 754 at the 2000 census.
Merrill is named for the seventh Governor of Iowa Samuel Merrill. The community was officially recognized on February 27, 1872. and became a incorporated city on April 24, 1994. Merrill is among the oldest towns in northwest Iowa.
In 2007, the city hired Drake University public relations seniors to research and develop strategies to attract new residents.