- 18April 18, 1819No events
- 19April 19, 1819No events
- 20April 20, 1819No events
- 21April 21, 1819No events
- 22April 22, 1819No events
- 23April 23, 1819No events
- 24April 24, 1819No 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.