In the United States, the best place to start is with the granddaddy of them all, the Road Runners' Club of America (RRCA). Not only can you find local and national club listings through the RRCA, you can get an idea of what's happening with running across the country.

To find clubs in the state where you live or a state you're planning to visit, you can go straight to a map on their Web site, click on the state, and immediately access a list of all the running clubs in that state. The RRCA's full contact information is as follows:

RRCA National Office

1501 Lee Highway, Suite 140
Alexandria, VA 22209
Phone: (703) 525-3890