Focused on Adair County, Missouri, including Kirksville and surrounding areas, this collection encompasses a wide variety of materials from businesses, churches, and organizations. It includes correspondence, newspaper clippings, photographs, maps, and more.

Record Book containing congregation's petition for affiliation with the Palmyra Presbytery, Presbyterian Church USA; Session Minutes, 1892 February 8 - 1906 December 4; Congregational Meeting Minutes, 1905 October 31; and Membership Roll, 1892-1906.

An abstract of a register with a partial roster of the pastors, marriages, infant baptisms and memberships for November 1898 through August 1907.

The Kirksville photograph archives consist of subject folders on people, places, and events related to Kirksville, Missouri.

Miscellaenous documents spanning the years 1883 to 1968 related to Kirksville, Missouri, Presbyterian Churches. These include The Cumberland Presbyterian Church which was organized in Kirksville in May 1846 and the Northern, or Old School, Presbyterians (Presbyterian Church (U.S.A.) organized during the Fall of 1859. These two congregations merged in 1906 under the name First Presbyterian Church.

The vertical files consist of subject folders on people, places, and events related to Missouri history in Adair County, Kirksville and Northeast Missouri. Materials include articles, newspaper clippings, press releases, biographical information, fliers, and other ephemeral materials.

This collection includes P. O. Selby's personal papers, research notes and writings and includes the files and records he gave during his lifetime as well as those found in his campus office after his death. The majority are concerned with Kirksville and Adair County history, genealogies of Adair County families, and Mark Twain.