USA Cycling: Promoting all types of bicycle racing. You can buy your race license here.
IMBA (International Mountain Bicycling Association): Supports mountain bike riding, trail building, and grass-roots advocacy
ROC (Ride Oswego County): Local bicycling club
Great Bear Farm: Local mountain bike trail system
Rice Creek Field Station: Part of SUNY Oswego, it also has a mountain biking trails.
Winona Forest: Multi-use trails partially in Oswego County