Concern about overuse leading to erosion has led the Peruvian government to place a limit on the number of people who may hike this trail per season, and to sharply limit the companies that can provide guides. As a result, advance booking is mandatory. A maximum of 500 people are allowed on the trail each day, of which only 200 are trekkers, the rest being guides and porters. As a result, the high season books out very quickly.
The trail is closed every February for cleaning. This was originally done informally by organizations such as South American Explorers but is now managed officially.
Trekkers normally take four or five days to complete the "Classic Inca Trail" but a two day trek from Km 104 is also possible.
It starts from one of two points: 88 km (55 miles) or 82 km (51 miles) from Cusco on the Urubamba River at approximately 2,800 metres (9,200 ft) or 2,600 metres (8,500 ft) altitude, respectively.
Both of these trail segments meet above the Inca ruins of Patallaqta (sometimes called Llaqtapata), a site used for religious and ceremonial functions, crop production, and housing for soldiers from the nearby hilltop site of Willkaraqay, an ancient pre-Inca site first inhabited around 500 BC. The trail undulates, but overall ascends along the Kusichaka River.
At the small village Wayllapampa ("grassy plain", Wayllabamba) the trail intersects with the "Mollepata Trail" at 3,000 metres (9,800 ft).
Small, permanent settlements are located adjacent to the trail, and Wayllapampa has approximately 400 inhabitants (130 families) spread along this portion of the trail. Pack animals—horses, mules, donkeys, and llamas—are allowed.
At Wayllapampa the trail to Machu Picchu turns west and begins ascending along a tributary of the Kusichaka. Because of previous damage caused by hooves, pack animals are not allowed on the remainder of the trail. For the same reason, metal-tipped trekking poles are not allowed on the trail.