The Still River is located in southwestern Connecticut. From its origin on the New York border, it passes through Danbury and flows northward to its junction with the Housatonic River in New Milford.
Interpretation of the Still River's history is based on its surficial geology and bedrock topography. High bedrock surfaces to the south, east, and west of the river show that its preglacial direction was probably to the north. The Still River has developed along the easily eroded Inwood Marble as a subsequent tributary to the Housatonic.
Pleistocene glaciation left a variety of deposits in the Still Valley. The oldest of these is the 'lower' till, of either Illinoian or Altonian age. This till unit is overlain in turn by the Woodfordian 'upper' till. The upper till has basal and ablation facies. Ice-contact deposits formed in the fringing stagnation zone of the last retreating ice sheet. As the glacier withdrew along the Still Valley, preglacial Lake Danbury was impounded against the highlands to the south. Glacial retreat opened progressively lower outlets for this lake. Its final stage was contained by a till (?) barrier at the Housatonic Gorge in New Milford. Filling of the lake by glacial outwash was soon followed by downcutting of the dam and establishment of the modern Housatonic and Still River channels.