Absolutely a tobacco pipe. One interesting thing about clay pipes is that the diameter of the hole in the stem progressively decreases as the pipes become more recent. Probably because stem lengths were progressively decreasing. Although only 'verified' for pipes originating from Britain, it does at least provide some indication of date for clay pipes in general. Building on work by J. C. Harrington in the 1950s (he examined thousands of pipe stems excavated at Jamestown and other colonial Virginia sites) Louis Binford later devised a mathematical formula from which he derived the following table (the cut-off dates are of course not absolute):
9/64" bore dates to 1590-1620
8/64" bore dates to 1620-1650
7/64" bore dates to 1650-1680
6/64" bore dates to 1680-1720
5/64" bore dates to 1720-1750
4/64" bore dates to 1750-1800
The easiest way to check the bore is with set of small steel drill bits. Carefully insert the bits into the stem hole until you find one that fits exactly.