Piedras Marcadas ("Marked Rocks") is the northernmost site along the roughly 17-mile edge of lava flow just northwest of Albuquerque, forming a significant part of the Petroglyphs National Monument. The trail has the most to see of the three petroglyph sites in the park, in terms of petroglyph density, and is located close to a residential area. Once on the trail, however, the area feels much more remote as the homes and businesses fade into the distance.

The petroglyphs, formed by scratching the surface of the hard black coating covering the lava boulders, are estimated to be 400-700 years old. The newer formed glyphs are brighter, as the older ones continue to accumulate new coatings from the constant weathering. Recently (2021), the paths have had cabling placed alongside the trail to prevent people from ascending up into the rocks for a closer view. It was fortunate for the author that the close-up viewing was permitted at the time of his hikes, resulting in the collection of photos presented.