Calamus () is a small town in Clinton County, Iowa, United States, located on the historical Lincoln Highway, which was the first transcontinental highway for automobiles across the U.S.. Calamus is the only town in Olive Township and had a population of 356 at the 2020 census, which was a 9.6% decrease from 2000. Calamus was named after Calamus Creek, which received its name from the great quantities of sweet flag growing in it, derived from the botanical name Acorus calamus, commonly called Sweet Flag or Calamus. History Early settlement In July 1858 the first railroad was built west from Clinton to Clarence, Iowa. It was called the Chicago, Iowa and Nebraska Railroad, later changed to Chicago Northwestern Railroad Co.. In the same year, Joseph D. Fegan was deputized to go to the cross roads of the Stage Coach Lines and the Indian Trails at Syracuse, which had a small stove and a saloon, to establish a post office in 1858. No one could suggest a name and Mr. Fegan asked "Is there no creek or anything?" "Yes, Calamus Creek." "Then let it be Calamus." Due to the large hazardous swamps, the Post Office and railway station were moved to a more favorable location in what is now the town of Calamus. The present day location of Calamus, a small village on the Union Pacific Railway, was platted in 1860 by R. S. Dickinson, who owned the land on the north side of the railroad, and Col. Milo Smith, who owned that on the south. James Keith opened the first store here containing a small stock of groceries and accessories, located about where the present day Faith Lutheran Church stands. In 1861, R. S. Dickinson and his son A. L. built the first general store, and opened a large and complete stock of general merchandise, and engaged in grain-buying. Two or three years later, another small store was opened by R. E. Houck. Thomas Franklin Butterfield built the first grain elevator, to care for the grain which had previously been hauled to Davenport. In 1868, two elevators had a thriving business and there were four general stores. The first hotel was built in the early 1860s and burned down in 1912. This building was located on the S.W. corner of 2nd and Railroad Streets and the first landlord was William Wick. Later the "Commercial Hotel" was erected on 2nd St.