Cathan is a former census-designated place (CDP) in Snohomish County, Washington, United States.

As of the census[1] of 2000, there were 526 people, 176 households, and 136 families residing in the CDP.

There were 181 housing units at an average density of 68.2/sq mi (26.4/km2).

There were 176 households, out of which 38.6% had children under the age of 18 living with them, 65.3% were married couples living together, 8.0% had a female householder with no husband present, and 22.7% were non-families.

14.8% of all households were made up of individuals, and 0.6% had someone living alone who was 65 years of age or older.