Killen, in Lauderdale County, was settled in the early 1800s. In 1826 Joseph Mason became the first postmaster of a community called Masonville, whose post office lasted until 1866.
More about Killen
The town grew with the canal built around the shoals of the Tennessee River. Construction of the Alabama Canal in the 1830s brought early growth, and work on a new canal began in 1875; the 14 1/2-mile canal, with nine locks and a lift of 85 feet, opened on November 10, 1890, and was renamed the Muscle Shoals Canal. Lock Six, its headquarters, stood half a mile south of town, and in 1885 the Corps of Engineers employed 200 men, many of whom built homes nearby.
In 1895 James Sharp Killen built a general store and applied for a post office, sending three possible names; Killen was chosen, and the post office opened on August 22, 1896, the founding of the town. Killen was incorporated in 1957.
Sources
The Historical Marker Database: Town of Killen (Alabama Tourism Department and the Town of Killen)
Wikipedia: Killen, Alabama