Available evidence supports that approximately half of North Carolina's population resides in a small number of counties, though the exact number cited varies slightly between 12 and 13 counties.
50% of all North Carolinians live in just 12 counties!

North Carolina - Wikipedia
Source: en.wikipedia.org
Key Evidence
Carolina Demography reports half of North Carolinians live in 13 counties.
carolinademography.cpc.unc.educarolinademography.cpc.unc.eduHalf of North Carolinians Live in These 13 Counties
A Facebook post by Carolina Forward claims half live in 12 counties but lacks detailed data.
facebook.comfacebook.com50% of all North Carolinians live in just 12 counties! And
Other demographic sources provide context but do not specify this statistic directly ( to ).
en.wikipedia.orgen.wikipedia.orgDemographics of North Carolina
en.wikipedia.orgen.wikipedia.orgNorth Carolina
What the Evidence Shows
The claim states that 50% of all North Carolinians live in just 12 counties.
(a Facebook post by Carolina Forward) explicitly states this claim but does not provide detailed data or methodology, so it is a secondary source with limited detail.facebook.comfacebook.com50% of all North Carolinians live in just 12 counties! And
(Carolina Demography, a reputable demographic research group) provides a closely related figure: about half of North Carolina's population lives in 13 counties, not 12. This source is more authoritative and based on demographic analysis.carolinademography.cpc.unc.educarolinademography.cpc.unc.eduHalf of North Carolinians Live in These 13 Counties
The slight discrepancy between 12 and 13 counties may be due to rounding, different data years, or definitional differences in county inclusion.
Other sources provide general demographic context but do not directly confirm or refute the exact number of counties containing half the population.carolinademography.cpc.unc.educarolinademography.cpc.unc.eduNC’s senior population is growing, but where?
datausa.iodatausa.ioNorth Carolina+3 more
Given that the Carolina Demography source is from 2014 and the Facebook post is undated but recent, population shifts could have slightly changed the count of counties representing half the population.
Overall, evidence strongly supports the core claim that about half of North Carolina's population is concentrated in a small subset of counties (around a dozen), with minor variation in the exact count.
Therefore, the claim is mostly true but should acknowledge that some sources say 13 counties rather than exactly 12.