RSCC established a "friendly relationship" with Jiaxing, China in September 2009.  It is hoped that after a period of negotiation and formal delegation exchange visits, Jiaxing will become Rockville's second sister city.  RSCC is expanding its activities to include Chinese cultural activities in addition to our usual German events.

In 1987 we became a privately incorporated not-for-profit 501(c)(3) organization, promoting a people-to-people program initiated in 1956 by President Eisenhower which, under the umbrella organization, Sister Cities International (SCI), is one of over 2,500 partnerships in 132 countries. These partnerships provide an opportunity to pursue initiatives through projects promoting peace through mutual respect, understanding, and cooperation - one individual, one community at a time. 

Rockville Mayor Dickran Hovsepian and the City Council approved a resolution on October 13, 1957, establishing the Sister City relationship with Pinneberg, Federal Republic of Germany. A similar resolution was passed on November 8, 1957, in Pinneberg. On November 8, 1982, the Mayor and Council of Rockville adopted a resolution to establish a Sister City Task Force. The mission of the task force was to formulate new programs and strengthen existing ties between the two cities.

An official delegation from Pinneberg visited Rockville in October 1983 for a two-week stay. The visit was highlighted by a White House ceremony with the President of West Germany and the President of the United States.

In July 1983, June 1985, and July 1987, groups of Rockville high school students visited Pinneberg and were hosted by German families. Groups of Pinneberg students visited Rockville in 1984, 1985, and 1986, and were housed with Rockville families. Since then, numerous exchanges of students and adults have occurred on a regular basis.

Rockville Mayor Steven Van Grack and council members Stephen Abrams, James Coyle, Douglas Duncan, and Peter Hartogensis visited Pinneberg in the fall of 1987 for the 30th anniversary celebration along with 18 representatives from the Rockville Sister City Corporation. Officials who have previously visited Pinneberg include former Rockville mayors Dickran Hovsepian, William Hanna, John Freeland, and Viola Hovsepian and State Senator Frank Shore.

The Pinneberg Friendship Gardens, on the grounds of the Civic Center and in front of Rockville City Hall, were dedicated in October 1984. The gardens contain rose bushes given to the citizens of Rockville by Pinneberg as a sign of our enduring relationship, and to commemorate the tricentennial of the arrival of the first German immigrants to the United States.

Rockville's Welsh Park, located at the corner of Mannakee Street and Martins Lane, is home to a sculpture by Pinneberg artist Gabrielle Schmidt-Heins. Titled "On Site," the work represents an early German tribal tradition of constructing a place for meetings and rituals. The sculpture was completed and dedicated in October 1991.

The Pinneberg Room on the second floor of the Rockville Civic Center Mansion (Glenview Mansion) is used to house a collection of photographs, newspaper clippings, and memorabilia of the partnership.

Rockville has a Pinneberg Avenue, located in the Twinbrook neighborhood; Pinneberg likewise has a "Rockvillestraße" [Rockville Street] in one of its neighborhoods.

Each city maintains an official guest book to record the names of individuals who have visited.