I've discovered four great resources, three being very useful data searches, that can help you localize your Thanksgiving -along with the rest of the year of course!
Eat Local First Local Flavor Guide

It's loaded with information about farmers' markets, local food producers & markets, a local dining map, reviews of local restaurants and more! All focused on the Denver Metro area.
Learn fun facts about restaurants and markets like how in the peak of the growing season, 75% of the produce served at Fuel is grown right here in Colorado!
Read more about the guide and see the list of locations where you can pick up a copy here.
Download a condensed printable version here.
Find What's Fresh & In Season in Your Region:

The NRDC has compiled a plethora of data on crop types, regions, and growing seasons. All of this information as been put into a searchable database so that you can look up what is in season when and where. Additionally, you can see what is available in other neighboring regions.