Actually there are more than 4 government holidays in a year. There is no mail delivery on government holidays. According to the USPS website here is a list of annual holidays that the USPS will be closed for in 2010:
First Class Mail is delivered in three to five days.
First Class Mail is delivered in three to five days.
First class mail takes 2-3 days delivery time in the US.
First class mail delivery takes 3 - 5 days.
First class mail delivery takes 3-5 days.
First Class Mail is delivered in three to five days.
First class mail delivery takes 3 - 5 days.
First Class Mail is delivered in three to five days.
First class mail delivery takes 3 to 5 days.
First class mail delivery takes 3 - 5 days.
. 3-5 days by express mail :)
Three to five business days by US mail.