The round-trip hike to the ruins of Pumamarca takes about 4–6 hours from Ollantaytambo [1] on a moderate, steadily climbing trail. The ruins of Pumamarca sit on a hillside overlooking the convergence of the Río Patacancha and the Yuracmayo (White River).
The well-preserved site was thought to be a checkpoint to control access to Ollantaytambo.
To reach Pumamarca, follow Patacalle out of town. Shortly after the first bridge, a large path leaves the main road to the right and follows the river. Follow this path for about 15 minutes until it rejoins the main road at the small town of Munaypata.
Just up the road you will see an electrical pole on the left labeled 2224 and a path leading behind the adjacent house. Follow this path uphill for 15 more minutes to a blue archaeological marker for the Media Luna terraces in front of you. At this point, follow the switchback up the hill to your right (and not the path in front of you toward the terraces). The trail continues to climb steeply but will soon become more gradual.
After another hour or so of hiking, the trail comes to a clearing with small waterfalls and the beginning of ancient aqueducts. The trail follows an aqueduct and in 20–30 more minutes the ruins of Pumamarca will become apparent on the hillside in front of you. The trail becomes less clear at this point, but you can take multiple routes through the terraced fields up to the ruins (the main entrance is on the right side of the complex).
At times there is someone working at the ruins who can provide information, but if not there is currently no entrance fee or hours when the ruins are closed. After exploring the ruins, you can return to Ollantaytambo by the same path or you can descend the hillside to the town of Pallata and take the road down from there.
Links:
[1] http://www.moon.com/destinations/peru/the-sacred-valley/ollantaytambo