If a due date falls on a Saturday, Sunday, or legal holiday, then the date for filing is automatically extended to the next business day. For example, if May 1 falls on a Saturday, then calendar year returns must be filed by the following Monday. The filing date is determined by the postmark on the envelope the return is mailed in. Your return is considered to be filed on time if it is addressed properly and is postmarked by the due date. The return must have sufficient postage.
Returns sent by registered mail are timely if the registration is postmarked by the due date.
The return receipt is evidence that the return was mailed. If you send your return by certified mail, the date stamped by the Post Office is your postmark date. The certified mail return receipt is evidence that your return was delivered. Where To File File your return with the Commissioner of the Revenue, Director of Finance, or Director of Tax Administration for the city or county in which you live. We have listed the mailing address for returns on the back of the income tax instruction booklet, or you can click address to see the list.