MRU was formed in 1973 with the signing of the Mano River Declaration by His Excellency Siaka P. Stevens, President of the Republic of Sierra Leone, and His Excellency William R. Tolbert, Jr. President of the Republic of Liberia.  The aim of the organization was to expand trade by eliminating trade barriers, increasing trade cooperation, and creating favorable conditions for expansion of productive capacity, and to secure a fair distribution of economic cooperation benefits.  The original Declaration has been complemented by 16 protocols that govern institutional arrangements and expand the scope of the organization’s mandate.  These include the 11th protocol on trade integration and the 15th protocol on defense, security, internal affairs, and foreign affairs.

In its early years, MRU operated four technical training centers to build civil servant capacity in the areas of Posts and Telecommunications, Forestry, Customs and Excise, and Maritime Affairs. It provided scholarships for nationals to attend universities in Member States with a view to building professional capacity, particularly in the public sector.  The Mano River Bridge linking Liberia and Sierra Leone was constructed in 1976.  Intra-regional trade in local goods was liberalized in 1981 and companies that met value-added and ownership requirements for local production could trade their products duty-free within the sub-region.  MRU helped establish the Union Glass Factory in Liberia and laid the groundwork for the establishment of a regional airline and sea links for regional travel.  It promoted the use of small mills to expand production and processing of palm oil; constructed regional roads to facilitate movement in relation to the Trans-African Highway and conducted studies for energy provision projects. 

Unfortunately, these projects were significantly impacted by violent civil conflicts that began in Sierra Leone and Liberia the late 1980s, during which thousands of refugees also migrated to Guinea.  The Union Glass Factory ceased operations and scholarship programs were halted.  The 70% harmonization of trade tariffs that had been achieved was not maintained.  Secretariat offices and equipment were damaged during the fighting and most staff left. 

The conflicts fundamentally disrupted cooperation among Member States and restarting MRU operations meant rebuilding relationships on a foundation of trust, security, and good governance.  In 2000, the MRU 15th protocol on security was adopted, forming a joint security committee and joint border security and confidence-building units involving Sierra Leone, Liberia and Guinea.  These security programs continue to the present day.

Post-conflict rebuilding of the broader MRU organization began in 2008 through human resources development and provision of equipment.  In addition to peace and security, the renewed organization continued to focus on trade, infrastructure, education, and agriculture, while also expanding its work to into other areas.  In recent years, MRU has introduced programs for rice and cassava production, election monitoring, water resources management, forest conservation, and women’s economic empowerment, among others.  It was instrumental to controlling the deadly Ebola Virus Disease outbreak by strengthening country capacity to control the epidemic and halt spread of the virus across borders.