Perimeter is an apt if somewhat overstated title for this trail. It skirts the edge of the town of Los Alamos from the NE to SW corners. Most of it is relatively easy, but it is punctuated with some sharp climbs and rocky technical bits. The trail is low enough to have escaped the great Los Alamos fire, so it remains nicely shaded in the pines and has suffered no fire-related erosion. There is an additional 2 mile stretch of the Perimeter Trail further SW of town, but it is not contiguous with the main Perimeter trail in town and requires a good bit of pavement to connect to.