It forms part of the northern boundary of Kenai Peninsula, and reaches on the east to within 12 miles (19 km) of Passage Canal, a western branch of Prince William Sound.
Historically small steamers entered and left on high water though the practice is now rare since most if not all the places that they went are now connected by road.
The smaller valleys are narrow and steep, but the larger ones frequently show by their U-shaped cross section the former presence of glaciers.
[2] The Seward Highway follows a portion of the southern edge of the Chugach State Park along Turnagain Arm.
Resurrection Creek flows into the south side of the arm about 20 miles (32 km) east of the main body of Cook Inlet, and with Sixmile Creek, 8 miles (13 km) farther east; with its various branches, it drains a large part of the northeastern portion of Kenai Peninsula.
Bear and Palmer creeks are the two producing streams of this part of the field, and both are connected with Hope by roads.
[2] Glacier Creek enters Turnagain Arm from the north, 12 miles (19 km) from its eastern end.
Bligh served as Cook's Sailing Master on his third and final voyage, the aim of which was discovery of the Northwest Passage.
[7] The eastern portion of Kenai Peninsula and the region about the head of Turnagain Arm present a succession of rocks, which as a whole are of remarkably uniform appearance and composition.
Evidences of a former period of glacial activity are seen on all sides in broad-bottomed U-shaped valleys, polished rock surfaces, and transported boulders.
The shores of Turnagain Arm afford frequent proof of ice action in glacial markings and striated pebbles.
[2] The east shore along the Kenai Peninsula, from the mouth of Turnagain Arm nearly to Kachemak Bay, is low and comparatively flat, but is for the most part heavily wooded.
The low country near Hope consists of a grassy tide flat, about 50 acres in extent, and a few miles of forest and occasional small swamps along the lower part of Resurrection Creek.
A third species of spruce (Picea mariana) is found in the small peat bogs, along with smaller Hudsonian plants.
Beyond this elevation are alder thickets, small patches of dwarf willows and birches, and vast stretches of waving grass from 1–3 feet (0.30–0.91 m) high.
[8] Still higher, the slopes and rounded backs of the ridges are cushioned with a mass of heather and heather-like shrubs, chiefly Empetrum nigrum.