| John Calder Brennan | |
| Birth Date: | 19 November 1908 |
| Resting Place: | St. Lawrence Cemetery, Sumter County, South Carolina |
| Education: | B.A. English and History, Law Degree |
| Alma Mater: | The Citadel (1930), George Washington University (1937) |
| Known For: | Local and national historian |
John Calder Brennan (November 19, 1908 – February 6, 1996[1]) was a Laurel, Maryland historian.
A member of the class of 1930 at The Citadel, where he majored in English and History,[2] Brennan retired as a personnel specialist for the Federal Reserve.[3] He was a Laurel resident for more than 50 years[4] and wrote a column on history and etymology for the Laurel Leader newspaper in the 1960s and 1970s. Considered a Booth scholar, Brennan wrote the article "John Wilkes Booth's Enigmatic Brother Joseph", published in the Spring 1983 issue of Maryland Historical Magazine.[5] Also among Brennan's works is The Three Versions of the Testimony in the 1865 Conspiracy Trial, published in 1983 and cited in the book Blood on the Moon: The Assassination of Abraham Lincoln.[6] The Laurel Museum's research library is named after Brennan, whose works are among its major holdings.[7] A World War II veteran who served as a Major in the U.S. Army Air Corps, Brennan is interred at St. Lawrence Cemetery in Sumter County, South Carolina.[8]