Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_55864 ( "CERCLIS ID" text, "Name" text, "County" text, "Proposed" text, "Listed" text, "Construction completed" text, "Partially deleted" text, "Deleted" text )

### Question ###
In what county is the entry that has a Construction Completed date of 07/19/2000 and a Listed date of 09/21/1984 located?

### Accurate SQL ###

SELECT "County" FROM table_55864 WHERE "Listed" = '09/21/1984' AND "Construction completed" = '07/19/2000'