Alot of people are rushing around today to finish their tax forms and get the April 15 postmark. That brought up an interesting question in the office that we were unsure of the answer.Does the postmark have to be U.S. postal service? Hypothetical situation:Let's say you are travelling to some far off place (ex. Siberia). You get the bright idea to take your tax return along and mail it from there hoping your check will take a long time to get to the IRS. Does the far off place's postmark count toward the filing date?Just curious.