On the 12th of March 2001 in Cherniachovsk an agreement was signed on co-operation between Marijampolė Municipality and Cherniachovsk Municipality in Russia. By signing this agreement both municipalities decided to develop friendly relations in business, culture, education, sport and tourism, municipal, social support and care areas.
Cherniachovsk district, as well as Kaliningrad district, was established in 1946. The administrative center of the municipality is the town of Cherniachovsk. There are 7 rural districts. The population of Cherniachovsk Municipality is 58.4 thousand. Town is in a good economic - geographic location: two main highways cross the town: Western-Eastern (Kaliningrad, Cherniachovsk, Vilnius) and Northern-Southern (Bolshakov - Sovetsk - Riga).
There are a lot of historical, cultural and architectural monuments left in Cherniachovsk Municipality. Minerals like clay, peat and grit can be found in the territory of the Municipality. Inhabitants of Cherniachovsk Municipality mainly work in agriculture, building and construction, commerce and services. Cherniachovsk town has signed the co-operation agreements with Marijampolė and Vengozev (Poland) towns, it has also cultural relations with Kirchajmboladen and Krefeld towns in Germany and Bezje town in France.
- 2001 February 9 the Mayor of Cherniachovsk city G.I.Fomenko visited Marijampolė. The aim of this visit was to discuss possibilities of co-operation
- 2001 May 17-20 in the festival "City Days 2001" an art group from Cherniachovsk performed in Marijampolė
- 2002 May 25 delegation from Cherniachovsk participated in the annual festival "City Days 2002"
- 2002 September 14-15 official delegation from Marijampolė Municipality participated in the city days of Cherniachovsk
- 2003 May 30 - June 1 delegation from Cherniachovsk, led by the Mayor Galina Ivanovna Fomenko, visited Marijampolė during the festival "City Days 2003"
- 2003 October 10 delegation from Cherniachovsk visited Marijampolė. The aim of the visit - to share experience in the communal sphere
- February 20 2004 m. delegation of Marijampolė Municipality, led by the Mayor Mr. Vidmantas Brazys, visited Cherniachovsk during presentation of the project "International library - philosophical school"
- April - May 2004 in Marijampolė was organised exhibition of photography "Features of sister cities". There were presented photos of photographers from Cherniachovsk. Photographers participated in the exhibition opening ceremony in Marijampolė
- 2005 February 11-12 Marijampole visited newly elected Mayor of Cherniachovsk Mr. Andrej O. Vinogradov
- 2005 May 2-3 d. Marijampole P.Kriauciunas public library organised international conference for library workers. There were signed cooperation agreement with libraries from Cherniachovsk and Suwalki
- 2005 May 27-29 delegation from Cherniachovsk participate in Marijampole City Days festival