Pioneers settling in this area, including many Civil War veterans, bought five acres from the Burlington and Missouri River Railroad for $25 and established a school in 1875. Osco School District No. 6 deeded two acres for the Pleasant Prairie Graveyard in 1876, and the earliest known burials took place that year. More acreage was purchased in 1898, and the name was later changed to Osco Cemetery. It is the oldest organized cemetery in Kearney County.
Two monuments honoring veterans are located in the cemetery, the newest one having been erected in 1995. On Memorial Day, formerly "Decoration Day," veterans' organizations from Campbell, Upland, Minden, and Heartwell have helped recognize the Osco veterans. Children from Osco School also took part.
The cemetery never affiliated with a church, but kept its ties to the school. Volunteers have always seen to the upkeep of both. In 1949 the Osco School closed its doors and was purchased by the Osco Cemetery Association. Through the years the building was used for cemetery meetings, as a polling place, and for serving lunch on Memorial Day.