In August of 1850 Benjamin Lamb left Floyd County, Indiana with his family to head west. In September the family arrived at Garden Grove, Decatur County Iowa. He and his sons left the rest of the family there to travel further west looking for a location to settle which they found on section 26 of Pleasant Township. They built 2 cabins but had no supplies to live on for the coming winter. They moved on to Council Bluffs but it was so crowded that they could not find a place to stay. Once more they hitched up their horses and headed south to St. Joseph, Missouri where they were able to by supplies to live on. On 01 February 1851 they moved back to their claim in Pleasant Township. By 1853, the Lamb family had seven neighbors including A.C. Cooper and Kencil Kent. The next year in March of 1854, the township was organized by Judge Norman Nun.

Bismark was the first town in the township, located in section 36 near a mill site woned by Isaac Reynolds. It was surveyed by A.J. White and contained thirty lots. The town had two streets, Oak Street ran north and south and Hickory Street ran east and west. Near Bismark was the Leas Cemetery. A post office, Olio located slightly northeast of the center of the township, was opened in Olio in 1856 and closed in 1864. A post office named Tingley was active from 1868 to 1881. On the latter date, the present town of Tingley in northern Ringgold County was established.

The location of Pleasant Township on the Grand River, Twelve Mile and Sand Creek streams and the plentiful supply of wood, the settlers came in fast. By 1860 the population was 238 people. The early settlers located on these streams because of timber, water and other resources. By 1880 the township boasted a population of 682. But, population began to decline because of westward movement. The main road or trail from north to south was know as the Dragoon Trace. It was this trail that the Indians were driven out of the Iowa to Kansas. Information from 1908 Union County History by George A. Ide.

Pleasant Township is the home of five cemeteries; Homewood Cemetery, Leas Cemetery, Oak Hill Cemetery, Reasoner Cemetery also known as Olinger Cemetery and Cornwall Cemetery also known as Haight Cemetery.