Training Center Petaluma is a Coast Guard training facility in the northern California counties of Sonoma and Marin. Formerly the installation was the United States Army "Two Rock Station". Approximately 4,000 military students train there each year. It is the only Coast Guard training center or large installation without a major operational component or waterfront. The training center is located in a rural area north of San Francisco at 38.25°N 122.79°W/ 38.25;-122.79.