Island County sheriff's deputies in the Ledgewood neighborhood on Whidbey Island were asking for identification for anyone trying to get into the area, The Seattle Times reported.
The neighborhood can only be reached on foot because the slide Wednesday blocked the only road.
"We want to be sure the area is kept secure and safe," Bill Oakes, Island County public works director, said Friday. "We realize people are interested in seeing the slide, but this weekend we must focus on making sure the slide is stabilized."
The slide was one of the largest ever in Washington state. It affected 20 homes, but most are now open for occupancy, while four are accessible only during the day and one is completely off limits.
The road could be closed for several weeks, officials said. Public works employees are trying to stabilize a footpath to allow it to be used by ATVs.
Whidbey Island, about 30 miles north of Seattle on the northern edge of Puget Sound, is one of the longest in the United States.