I've found what must be the longest aged rye whiskey around. A bottle of Very Ancient Pure Rye Whisky. Here's what the label reads on this beautiful old pint:

This medicinal whisky is hereby guaranteed by the distiller and S.S. Pierce Co. to be pure Maryland Rye. 25 Years in Wood.

Bottled from Barrel serial No. 164752, Manufactured in Year 1902. 100 proof.
The Hannis Distilling Co., The American Medicinal Spirits Co., Successor.

In back, there's a small label that reads as follows:

Warning: This bottle has been filled by the S. S. Pierce Co. under provisions of the National Prohibition Act. Contents for medicinal purposes only.

This bottle could be purchased only from a 'Retail Druggist' on a duly authorized physicians prescription. If purchased otherwise, both seller and purchaser were subject to prosecution for violation of the Prohibition laws. S.S. Pierce Co. Boston, Mass.

If there's a rye whiskey out there aged longer than 25 years, please let us know.