Steilacoom Tribal Cultural Center and Museum, a former church on Lafayette Street, Steilacoom, Washington. – Joe Mabel, CC BY-SA 3.0 – Wikimedia Commons Steilacoom is located in Pierce County. About 6,727 people live here (as of 2020). Between 2010 and 2020, the population grew from 5,985 to 6,727. The region is at 23 meters above sea level. The area covers about 5.4 square kilometers. There are about 362 streets in Steilacoom. The postal codes are 98388. The dialing code is 253. Steilacoom is town in Washington, United States. Among other things, Steilacoom has public Transport, restaurants, cafés and hairdressers. More information at townofsteilacoom.org.