The NCCN Mountain Lakes Monitoring Program (Glesne et al. 2012) was developed to characterize and detect substantive trends within a representative set of subalpine lakes in each of the three NCCN parks. The primary focus of this program centers on the detailed monitoring of physical, chemical and biological trends in the same 20 core reference lakes sampled annually. Of the 20 core lakes funded by the NCCN, six lakes are at MORA, six are at NOCA, and eight are at OLYM. A secondary focus of the program is to determine the status of a broader population of park lakes through the less frequent (once per decade) sampling of 40-50 lakes. This report pertains to only the 20 core lakes. All core lakes were selected randomly from a subset of the entire population of similar lakes at each park. The subset, or sample frame includes lakes found entirely within park boundaries, ranging in size from 0.4 to 6.0 hectares, occurring at elevations from 1220 meters (4000 ft.) extending to the upper limit of the subalpine zone at each park, and which are not heavily influenced by glacial runoff. Lakes were also required to have a maximum depth greater than 2.5 meters, be accessible within a two-day hike from a trailhead, and have low densities of fish. An additional sampling design objective was to disperse sample lakes across the wide range of annual precipitation categories found within these mountainous NCCN parks.