Try Googling
But it looks like 8 years
http://www.lexisnexis.com/hottopics/tncode/
*Quoting Tennessee Statutes § 40-2-101. - Felonies.
(a) A person may be prosecuted, tried and punished for an offense punishable with death or by imprisonment in the penitentiary during life, at any time after the offense is committed.
(b) Prosecution for a felony offense shall begin within:
(1) Fifteen (15) years for a Class A felony;
(2) Eight (8) years for a Class B felony;
(3) Four (4) years for a Class C or Class D felony; and
(4) Two (2) years for a Class E felony.
(c) Notwithstanding subsections (a) and (b), offenses arising under the revenue laws of the state shall be commenced within the three (3) years following the commission of the offense, except that the period of limitation of prosecution shall be six (6) years in the following instances:
(1) Offenses involving the defrauding or attempting to defraud the state of Tennessee or any agency of the state, whether by conspiracy or not, and in any manner;
(2) The offense of willfully attempting in any manner to evade or defeat any tax or the payment of a tax;
(3) The offense of willfully aiding or abetting, or procuring, counseling or advising, the preparation or presentation under, or in connection with, any matter arising under the revenue laws of the state, or a false or fraudulent return, affidavit, claim or document, whether or not the falsity or fraud is with the knowledge or consent of the person authorized or required to present the return, affidavit, claim or document; and
(4) The offense of willfully failing to pay any tax, or make any return at the time or times required by law or regulation.
(d) Notwithstanding the provisions of subdivision (b)(3) to the contrary, prosecution for the offense of arson as prohibited by § 39-14-301 shall commence within eight (8) years from the date the offense occurs.
(e) Prosecutions for any offense committed against a child prior to July 1, 1997, that constitutes a criminal offense under the provisions of § 39-2-601 [repealed], § 39-2-603 [repealed], § 39-2-604 [repealed], § 39-2-606 [repealed], § 39-2-607 [repealed], § 39-2-608 [repealed], § 39-2-612 [repealed], § 39-4-306 [repealed], § 39-4-307 [repealed], § 39-6-1137 [repealed], or § 39-6-1138 [repealed], or under the provisions of §§ 39-13-502 — 39-13-505, § 39-15-302 or § 39-17-902 shall commence no later than the date the child attains the age of majority or within four (4) years after the commission of the offense, whichever occurs later; provided, that pursuant to subsection (a), an offense punishable by life imprisonment may be prosecuted at any time after the offense has been committed.
(f) For offenses committed prior to November 1, 1989, the limitation of prosecution in effect at that time shall govern.
(g) Prosecutions for any offense committed against a child on or after July 1, 1997, that constitutes a criminal offense under the provisions of §§ 39-13-502 — 39-13-505, § 39-13-522, § 39-15-302 or § 39-17-902 shall commence no later than the date the child reaches twenty-one (21) years of age; provided, that if the provisions of subsection (a) or (b) provide a longer period of time within which prosecution may be brought than this subsection (g), the applicable provision of subsection (a) or (b) shall prevail.
(h) A person may be prosecuted, tried and punished for any offense committed against a child on or after June 20, 2006, that constitutes a criminal offense under the provisions of §§ 39-13-502 — 39-13-505, § 39-13-522, § 39-13-527 or § 39-15-302, no later than twenty-five (25) years from the date the child becomes eighteen (18) years of age.
