How many members were in the Ku-Klux-Klan in 1865?
If the year in this question is correct, this has the potential to be a trick question. The Ku Klux Klan was not formally established until 1867 when a general organization convention was held. By 1867, the Klan had clubs in all of the southern states. It became necessary to organize these clubs. At the convention, a former Confederate general by the name of Nathan Bedford Forrest was selected as the "Grand Wizard" of the Klan. Forrest was remembered for his slaughter of black Union troops and civilians after their surrender at the Battle of Fort Pillow. The Klan reached its peak of membership in the 1920's when it had a registration of over four million people.
In December of 1865, six former Confederate soldiers formed a social club to pass the time away. They jokingly used Greek letters like a college fraternity to name their club. Their initial meeting was more of a social gathering in Pulaski, Tennessee. Early on, they would drunkenly run the streets in white costumes. The result of this revelry was that the freed slaves were generally scared of these activities. This is how the group evolved into a racist terrorist organization. So a legitimate answer to the question would be that the Ku Klux Klan had a membership of six in 1865.