To the west the Milbanke Sound Group is bounded by the Pacific Ocean and elsewhere it is surrounded by adjacent islands that form an archipelago.

Although not related, the Milbanke Sound Group is close to the remains of a much older magmatic feature that was formed during the Tertiary period.

[4] Near the northeastern shore of Price Island, a small eroded monogenetic cinder cone composed of basalt is covered by mature forest.

[4] Helmet Peak on the northern end of Lake Island just off the southwestern side of the Don Peninsula is a steep-sided monogenetic cinder cone.

[3] During its eruption, basaltic tuff breccia was sent throughout the surrounding landscape that deposited on glaciated granitic rock and unconsolidated beach gravel near the volcano.

[4] At the southern end of the Milbanke Sound Group, a small monogenetic cinder cone with an elevation of 50 m (160 ft) resides on Dufferin Island.

[3] However, this grouping is not widely accepted because the volcanoes are much younger than other magmatic features at the western end of the Anahim Volcanic Belt.

[3] However, the volcanic group is near the remnants of a 14 to 12 million year old magmatic feature that is interpreted to define the westernmost end of the Anahim hotspot track.

[4] A possible explanation for the origin of the Milbanke Sound Group is that it reflects a northern extension of the north-west trending subduction-related Garibaldi Volcanic Belt further south.

[3] Currently, the Milbanke Sound Cones are not monitored closely enough by the Geological Survey of Canada to ascertain how active their magma chambers are.

[13] An existing network of seismographs has been established to monitor earthquakes, but is too far away to provide a good indication of what is happening beneath the cones.