The due date for the filing of Arkansas individual income tax returns shall be as follows:
A tax return is "filed" with the Department at the time and date it is actually received by the Department. However, there is one exception to this rule for tax returns mailed to the Department through the United States Postal Service. ACA 26-18-105. This statute states that the postmark date on the envelope containing the tax return (or returns) shall be considered the return's filing date with the Department. Only tax returns mailed through the United States Postal Service qualify for this filing break. Tax returns sent through private carriers such as United Parcel Service or Federal Express will be considered "filed" when such returns are actually received by the Department. If the due date falls on a Saturday, Sunday or legal holiday for which the Department is closed in observance of, the due date shall be the next working day that the Department is open for business.
1.26 Ark. Code R. 51-806(a)