The Washington Post Office, Library, City Hall, Mini Bus Services, and County offices will be closed tomorrow in observance of the Labor Day Holiday. State and federal offices will also be closed, as well as the conservation Center at Marr Park, west of Ainsworth. Traffic is also expected to be busy during the holiday. A Triple-A-Iowa spokesman says a ten-percent increase over last year is expected, putting a total of more than 34 million drivers on the road this Labor Day weekend.