Sequim Bay drains an area of approximately 35,813 acres. Jimmycomelately Creek is Sequim Bay's primary subbasin; other significant subbasins draining to the Bay include Johnson, Dean, and Chicken Coop creeks. Sequim Bay has a surface area of approximately 7.6 square miles at mean lower low water, being about 3.5 miles in length and over a mile wide. Sequim Bay is almost totally enclosed by the formation of Travis Spit from the east.

Jimmycomelately Creek and Sequim Bay have long been important to the Jamestown S'Klallam Tribe as a major traditional hunting, fishing, shellfishing and gathering area for thousands of years.

In addition to summer chum salmon, coho salmon, winter steelhead and sea-run cutthroat trout are known to inhabit JCL Creek. Forage fish, such as sand lance and herring, also use the estuary for feeding and refuge, and their populations have been heavily impacted by shoreline development and the degradation of the estuary.South Sequim Bay also provides critical habitat for a wide variety of shellfish, and has been certified by the State for commercial shellfish harvest. In addition, many species of birds and mammals depend upon the estuary and bay during parts of their life history. Bald eagles, osprey, cormorants, kingfishers, gulls, ducks and geese, shorebirds, sea lions and otters all share in the abundant food supply of Sequim Bay.

Sequim Bay is affected by shoreline armoring & water quality issues, while the Sequim Bay estuary has faced many natural resource challenges in the last 100 years. The late 18th century brought logging, road development, railroad construction, and the dredging of waterways. During that time, wetlands were converted, drained, filled and eventually diked. The mouth of the estuary was filled to create a log storage yard along with access roads into the log yard. Jimmycomelately and Dean Creeks were channelized to allow straight drainage into the bay to accommodate the log yard. Straightening of the channel benefitted the logging operation, but was not good for salmon.

The Jamestown S'Klallam Tribe began the Jimmycomelately Creek and Sequim Bay estuary project in the early 1990s to address problems associated with declining fish populations and increased flooding.