This paper empirically examines the intersection of recent literature regarding the effect on wages of both labor market concentration and unionization, using a fixed-effects model controlling for both occupation and geographical area, applied to a combination of 2016 Current Population Survey data and labor market concentration data derived from the universe of online job postings in the United States. This paper found a positive effect of the interaction of unionization and concentration on wages in most model specifications, consistent with similar literature in other countries, but failed to produce significant results in the most granular model, likely due to attenuation bias exacerbated by large double fixed effects.