The natural bridge was discovered by David Gowan, a Scotsman, in 1877 while hiding from Apache Indians, and so impressed was he by the unusual, secluded location that he persuaded his family to emigrate and live there. Although they left in 1948 their lodge remains - since being included in the National Register of historic places - and forms the centerpiece of the buildings in the state park, which is reached by a short, paved side road (FR 583) that forks off AZ 87 11 miles north of Payson - this crosses a plateau sparsely covered by wildflowers and small trees, then drops steeply 800 feet to the canyon floor. The bridge is not immediately apparent, as beyond the park buildings stretches a flat meadow that seems to cover all the ground between the canyon walls. The creek actually runs a hundred feet below in a narrow gorge, the edge of which is hidden by trees, flows under the bridge beneath the meadow and continues downstream through a rather wider canyon. Depending on which dimension is used as a measurement, Tonto is the world's largest travertine bridge - 180 feet high, 400 feet long and about 100 feet thick on top.
The opposing sides of the valley receive unequal amounts of sun and exhibit very contrasting vegetation; thick pine trees on the northwest facing slopes but yucca, cacti and bushes on the southeast side, plus a variety of colors of exposed sandstone rock. A large number of bird species live in the different habitats, and besides watching them, the park is popular for picnics and hiking. One could probably explore the area by following the creek up or downstream for a few miles, or climbing the adjacent cliffs, but the official options are viewing the bridge from various overlooks
and walking along three short trails that start from the central meadow:
Gowan Trail - a route down the cliffs just below the bridge. This is quite steep and rather slippery in places but well worth the trip as it leads directly beneath, and in times of low water it is possible to walk through and link with the end of the Pine Creek Trail. High above, a small waterfall cascades over the edge of the bridge with more trailing grasses and ferns.
Pine Creek Trail - a longer path alongside the west side of the creek to a viewpoint beneath the bridge, a good place to appreciate the stalactite-like formations that hang from beneath the bridge and adorn the west-facing canyon wall - aptly described as an 'outdoor cave' by the park brochure. This trail has recently been extended to link with another path above (the short Anna Mae Trail).
Waterfall Trail - a very short path down into the canyon above the bridge to a grotto with hanging greenery, seeping water and travertine formations.