Henderson Inlet is the eastern-most inlet of WRIA 13 and has a total area of about 32,000 acres. It includes the City of Lacey and as of 1988, had a population of 38,066, with an expected 2010 population of 61,018. With more than 11 shoreline miles and extensive tidal mud flats, this inlet is home to large commercial shellfish operations. The inlet has an average depth of 25 feet, and reaches its maximum depth of 60 feet near the mouth (Thurston County et al. 1995). Woodard and Woodland Creeks are the largest tributaries to Henderson Inlet and drain about 80% of the watershed.

Much of outer Henderson Inlet is rural with some suburban development. The City of Lacey's urban core is nested in the Woodland Creek watershed near its headwaters. As a result, stormwater impacts are notable in Woodland Creek, giving rise to high flows in the winter and low or sub-surface in the upper reaches during the summer months.

Henderson Inlet streams are habitat for Deep South Sound coho and a small run of chum. The status of Henderson Inlet chum is currently unknown, according to the 2002 SaSI report.

Description from the Salmon Habitat Protection and Restoration Plan for Water Resource Inventory Area 13, Deschutes. For more information see the previously stated document or the Salmon Habitat Limiting Factors Final Report Water Resource Inventory Area 13