The Pleasanton-Tulancingo Sister City Association (PTSCA) was established in 1984 to promote a Sister-City relationship between Pleasanton, California, and Tulancingo, Hidalgo, Mexico.

Since then, many mayors, board members, civic leaders, community activists, business people, and students have traveled back and forth as delegates and ambassadors of cultural learning and experience.

The exchanges have crossed all types of organization, from fire departments to high school staff, from orphanages to recycling centers, hospitals to bridges, monuments, libraries and city halls. Often, delegations visit other cultural and natural.