Frequently Asked Questions

What is a sister city relationship?

A sister city relationship is a long-term, cooperative relationship between two cities in different countries through which cultural, educational, business, and technical exchanges take place. It is formalized when two mayors (or highest elected/appointed officials) sign a memorandum of understanding establishing a sister city relationship. Activities are usually organized and implemented by volunteers, local institutions, and municipal employees. A city may have any number of sister cities.

What do sister cities do?

Sister city organizations plan and implement cooperative activities and exchanges in cultural, educational, municipal/technical, business, and humanitarian fields. Thousands of inbound and outbound exchanges take place every year, as well as virtual exchanges and other remote, cooperative activities. 

What does Sister Cities International do?

Sister Cities International is a nonprofit member association for U.S. sister city organizations. Its staff provides assistance and expertise to over 500 member communities to help strengthen their sister city organizations. It shares best practices, provides grants and funding opportunities, assists with protocols and procedures related to sister cities, advocates for sister city organizations and international exchange, organizes conferences and meetings, publishes a printed and online directory of sister cities, networks among its membership, and provides other resources including certificates, discounted travel insurance, visa consultations, webinars, and toolkits, among other benefits.

How do two cities become sister cities?

A relationship is formally created when the mayors or highest elected officials from two communities sign a memorandum of understanding establishing the sister city partnership. However, this is usually the result of a long process that involves the local sister city organization along with the municipality and other local institutions. Sister city relationships may develop from a number of sources, including but not limited to: preexisting mayoral relationships, trade relationships, historical connections, ancestral/demographic connections, expatriate communities, shared geographic/sector challenges, faith-based groups, and personal experiences ranging from study/work abroad to marriages.

Who runs sister city organizations and how are they structured?

All of Sister Cities International’s members are independent organizations and have a number of management structures. Sister city organizations may be run by a group of volunteers, representatives from local institutions, the mayor’s office or municipal government, or by some combination of these. Most often sister city organizations are incorporated as 501(c)(3) nonprofits, although the municipal government may have representation or a formal relationship with the group. Many are governed by a board of directors or commission, although the majority of members are volunteers from all sectors of the community. They are most often organized by committee, with one committee for each partnership responsible for creating and implementing projects. Some sister city organizations are run by local institutions, such as a museum, cultural center, or chamber of commerce. Most municipal contacts for sister city organizations are in the office of the mayor, office of tourism/convention and visitors bureau, office of international affairs, office of protocol, or office of economic development.

How can I find out what my sister cities are?

Visit our online interactive directory at The online directory includes sister city relationships, contact information, and website/Facebook information for all current members. You can also view our 2017 Membership Directory and Annual Report

How can I get involved with my local sister city organization?

Visit our online directory at and search for your community. You should find the primary contact information for your sister city organization. If you don’t find your city it means they are not currently a member of the Sister Cities International network. You might try some basic research online or contact the town clerk, mayor’s office, or office of international affairs to see if they can put you in contact with your sister city organization. Most sister city committees have regular meetings that are open to the public.

What is the difference between a “Sister City” and a “Friendship City”?

The terms “sister city” and “friendship city” sometimes have different meanings. Generally speaking, friendship cities are less formal than sister cities. In some cities, “friendship city” is often used as a first stage in the relationship, and after it is strengthened and the partners are sure they want a long-term relationship they will become “sister cities”.