The river source is located 2 km (1.2 mi) south west of National Park in the Erua Forest.

[6] 1 kilometre up the Upper Retaruke Valley road is the location of the annual Kaitieke Collie club sheepdog trials.

Further up the valley there was a coal mine, and it was along the upper Retaruke river that fossil whalebones were found by Ken McNaught.

[citation needed] Portions of the Lower Retaruke Valley were settled about 1900 by government run farm ballot.

[8] The original vegetation was mainly rimu, rata, tawa, hinau, rewarewa, hard beech, and kamahi.

The highest and steepest hills in the Retaruke catchment have residual tawa-dominated stands or secondary growth of kamahi and some kanuka and rewarewa.