ARE professor Mitch Renkow has published a study analyzing the county-level labor market estimated for North Carolina for the period 2010-2015. The model accounts for inter-county commuting, migration, and within-county adjustments to labor demand changes. Econometric results indicate that, over the period considered, most of the new jobs in a particular county (about 84%) were taken either by people commuting in from other counties or by county residents who stopped commuting out to other counties.
In both metro and rural counties, the largest share of new jobs were taken by in-commuters. In metro counties, job growth resulted in a variety of adjustments (increased immigration, reduced out-commuting, new residents moving in and reduced unemployment). By contrast, the main impacts of job growth in rural counties were reduced unemployment and (especially) increased numbers of people commuting in to the county for work.
Review the research by visiting go.ncsu.edu/employment-growth-report.