- 05April 5, 1801No events
- 06April 6, 1801No events
- 07April 7, 1801No events
- 08April 8, 1801No events
- 09April 9, 1801No events
- 10April 10, 1801No events
- 11April 11, 1801No events
A=ANNUAL
M=MONTHLY
Q=QUARTERLY
DISCLAIMER: THESE DUE DATES ARE SUBJECT TO CHANGE. WE WILL DO OUR BEST TO KEEP THIS CALENDAR UP TO DATE WITH THE EVERCHANGING DEADLINES. ANY STATE FILING DUE DATES ARE IN REFERENCE SPECIFICALLY TO THE WASHINGTON STATE DEPARTMENT OF REVENUE.