Selection from novel orchardgrass (Dactylis glomerata L.) germplasm sources resulted in the development of a late-maturing orchardgrass population. This population comprises 58 families that were evaluated with 5 commercial cultivars under frequent and infrequent harvest intervals at two Cache County, UT, USA field locations during 2013 and 2014. The objective of this study was to characterize the performance of individual families when compared to check cultivars Intensive and Latar. Across locations and harvest intervals, individual families produced greater herbage dry mass and nutritive value than the check cultivars did, i.e., up to 12% greater herbage dry mass than that of the highest check, Intensive, and 1% (neutral-detergent-fiber digestibility) to 14% (water soluble carbohydrates) greater forage quality than that of the corresponding highest check cultivar. However, there were substantial genotype-by-environment interactions between families and locations, but not harvest intervals. Because of this, results were analyzed across harvest intervals but within locations. Within each location, there were families that possessed similar or greater maturity, herbage dry mass, in vitro true digestibility, and neutral-detergent-fiber digestibility at both locations. Overall, on the basis of the performance of its component families, this late-maturing orchardgrass population exhibited potential for developing improved cultivars.