The 1894 Polk Directory for Everett and Snohomish County included the names of residents of the various cities and towns listed by the specific locality; information for the "rural" section of the directory came from the County Assessor's office. The LOCALITY column gives the name of the Post Office to which "tax bills" were sent, and not necessarily the actual locality in which the individual lived.
Some of these "Post Office Addresses" were not in Snohomish County - McMurray is in south central Skagit County, and Cherry Valley is in north central King County. The SD# column refers to the SnoCo Supervisor District map (from 1926) indicating in which general area the Post Office was located. Supervisor's District #1 was all the area north of Everett to the Skagit County line. Supervisor's District #2 was south of Everett to the King County line. Supervisor's District #3 included the area east of Everett.
In using these data tables, remember that these were the names of people who owned property and were NOT listed in a particular city or town section of the 1894 Polk Directory.