Below is the Rediscovering Armenia Guidebook information about Garni Gorge.
The Garni Gorge* and Khosrov Reserve entrance by car: Though the Garni Gorge can be entered on foot by taking a steep, rough path from the left side of the temple parking lot, one can also drive. The first of two vehicle entrances to the Garni gorge is reached by taking the paved road to the right about 1 km W of Garni. Continue straight over the bridge, then turn left at the cement wall (straight goes to a mysterious Physics Institute), and left again on the dirt road where the dachas begin. A narrow dirt road, barely passable for street cars, descends into the gorge and E along the river past wonderful rock formations and pleasant picnic places, joining up with the other road from Garni village. Note that beyond the Physics Institute, another road dead-ends at the bottom of the gorge at a small hydropower station. There is a footbridge across the river just upstream, leading to an excellent set of walking trails following the river.
The Garni cobbled road into the gorge is also the route to reach the entrance to the Khosrov Nature Reserve, and an excellent jumping off point for Havuts Tar Monastery. The preserve takes its name from King Khosrov III, who ordered the planting of a massive forest to repair centuries of deforestation. Enter Garni village via the right fork at the WWII memorial. Continue straight till the road runs up against a large building, the House of Culture. Go left, then take the first significant dirt road right. Angling slightly right at the bottom, a steep, white-cobbled road (an icy deathtrap in winter) leads into the gorge. Turning right at the bottom of the gorge takes one along the Garni river, to the 11 c. medieval bridge, strange columnar basalt cliffs, colonies of house martins and swifts, lush greenery, and a series of picnic spots. Turning left, one bumps along a stream-traversed dirt road, past fishponds, across a bridge and up the far side of the gorge. At the top of the saddle is a padlocked cable across the road. The Khosrov Reserve guards at the gatehouse beyond may let you in, if you tell them you are visiting the “Surp” (St. Stepanos church, see below). Officially, prior permission to pass must be obtained from the Ministry of Nature Protection in Yerevan or from Mr. Samvel Shaboyan, Director of the Khosrov Reserve, based in the town of Vedi (phone 21332). Just before the guard house, clambering up the hill to the left and back, you will find a footpath that quickly widens, following the contours east about 40 minutes to Havuts Tar, passing khachkars along the route.