The pass stretches 5.5 km from northeast to southwest with two roughly right-angle bends, one at each end.
It was named for the USCS Active, a United States Navy survey vessel, the first steamer to navigate the pass in 1855.
It is also used by pleasure craft, fishing boats, freighters and freight ferries, making it very 'active' commercially as well.
However, strong eddies and tide rips are always present in the pass, making it a hazardous corridor for smaller vessels to transit.
A variety of wildlife may be seen in the pass, including harbour seals, sea lions, bald eagles, and orcas.