The Twin River's watershed covers 203 km2 (78 sq mi),[6] and its mean annual discharge is an estimated 16.7 m3/s (590 cu ft/s).

[6] The mouth of the Twin River is located about 77 km (48 mi) east-northeast of Wrangell, Alaska, about 114 km (71 mi) northwest of Stewart, British Columbia, and about 130 km (81 mi) south of Telegraph Creek, British Columbia.

This large glacial field is named after the son of Olav Mokievsky-Zubok, a glaciologist who carried out significant glaciological work in the Coast Mountains from the 1960s to the 1970s.

About 3.5 km (2.2 mi) north of the Iskut River the Twin River is joined by its west fork tributary, flowing south from another lobe of Twin Glacier.

About 6 km (3.7 mi) north the two lobes merge in the main body of Twin Glacier.