To fill labor requirements caused by the Civil War, the Union army impressed Kentucky slaves to work on various construction projects, especially transportation and communication initiatives involving roads and railroads. Loyal owners were paid for their slaves' work, but many grew annoyed at the loss of power and the army's demands. After Camp Nelson was established in 1863, impressed slaves from local farms provided much of the labor to construct the earthen fortifications and improve the roads that brought men and materials to this supply base. The following year, when blacks were finally allowed to enlist, many of these former laborers became soldiers who trained at Camp Nelson.