Explore California Historical Landmark #1 here at Monterey State Historic Park. The Custom House was the center of trade at a time when California was a part of Mexico and Monterey was the capital city. Delve into the commerce, politics, and social life of CA’s first capital while exploring this nearly 200-year-old adobe. This program aligns closely with 4th grade curriculum, but is also appropriate for students 3rd-5th grades.