Jason Biermann, of Snohomish County Emergency Management, said 15 victims have been identified by the Snohomish County medical examiner and six have yet to be identified.
Another four bodies were found in the debris field at the weekend and about 30 people remain missing after the massive mudslide struck the mountainside community of Oso on March 22.
Families coping with the loss of friends and neighbours sought comfort in church services as crews worked to recover more victims from the huge pile of mud and debris.
Rescue crews said many of the dogs that have been essential in the search for victims would be taking a two-day break.
Conditions in the area are treacherous, with septic tanks and other hazards.