In 1960 the City of Davenport formed the Sister Cities Committee to support and maintain an emerging relationship with Kaiserslautern, Germany. Kaiserslautern, (kizers-law-tern), Germany and Davenport, Iowa became sister cities on June 10, 1960 under the National League of Cities. Having experienced tremendous growth and success, in 1967 the sister city program of the National League of Cities became the independent organization Sister Cities International.

Over the years new relationships were formed with communities around the world with the purpose of advancing cultural understanding and citizen diplomacy, including new international relationships for Davenport, Iowa. Ilheus (il-yea-us), Bahia, Brazil and Davenport, Iowa became sister cities on January 31, 2005.  Vice-Prefeito Newton Lima came to Davenport, representing Ilheus, to sign the proclamation along with Davenport’s Mayor Edwin Winborn. Carlow County, Ireland became Davenport’s third sister city on September 26, 2006.  Davenport’s Mayor Edwin Winborn went to Carlow County, Ireland to sign the proclamation along with Cathaoirleach (ko-heer-loch) Michael Abbey, representing Carlow County.

Since the addition of Carlow County as the final sister city, the organization has also added Friendship Cities of Colon, Mexico in 2012 and Langfang, China in 2015, where community partnerships are still being established.