Lonoke County, Arkansas. Lonoke County is a county located in the Central Arkansas region of the U.S. state of Arkansas. As of the 2010 census, the population was 68,356, making it the eleventh-most populous of Arkansas's seventy-five counties. The county seat is Lonoke and largest city is Cabot. Lonoke County was formed on April 16, 1873 from Pulaski County and Prairie County, and was named as a corruption of lone oak, after a large red oak in the area that had been used by a surveyor to lay out the Memphis and Little Rock Railroad.