With more than 3,700 described species, stoneflies (Order Plecoptera) are an important component of global aquatic biodiversity. The meltwater stonefly Lednia tumana (Ricker, 1952) is endemic to alpine streams of Glacier National Park and has been petitioned for listing under the U.S. Endangered Species Act (ESA) due to climate change-induced loss of alpine glaciers and snowfields. Here, we present de novo assemblies of the nuclear (similar to 520 million base pairs [bp]) and mitochondrial (15,014-bp) genomes for L. tumana. The L. tumana (Family Nemouridae) nuclear genome is the most complete stonefly genome reported to date, with similar to 71% of genes present in complete form and more than 4,600 contigs longer than 10-kilobases (kb). The L. tumana mitochondrial genome is the second for the family Nemouridae and the first from North America. Together, both genomes represent important foundational resources, setting the stage for future efforts to understand the evolution of L. tumana, stoneflies, and aquatic insects worldwide.