Knoxville/Maryville area Tri clubs

I would call the bike shops in the area.  If they sell tri bikes, they'll know of the local tri clubs.  Pools with lap lanes (such as Aquatic Center at UT) may have a masters group and would know of tri clubs.  (Check the master's website for local masters swim sessions.)  There is a tri on the UT campus in April (TriDeltathon?) that uses the Aquatic Center for the swim.  If there are specialty running stores in K-town, that'll be a good place to check as well.  There is actually a semi-tri-specific store in the area, but I don't know the name of it offhand.

TriFind.com has a listing of many of the triathlons and duathlons in TN (and all 50 states).  Here is the link and you may be able to find club names and sponsor or race director contact info on races in your area.  http://www.trifind.com/tn.html

Hope this helps!