The Foundiougne Bridge, built by China over the Saloum River, will cut the cost in time and money of travel and transport among the West African countries of Gambia, Guinea-Bissau and Senegal, Xinhua says, quoting Senegalese President Macky Sall.
The bridge will link the three countries more closely, Mr Sall said when it was formally added to the road network last Saturday, the Chinese government-run news agency reported three days later.
The bridge is 1.6 km across, making it the longest steel-built river crossing in West Africa, The report says.
It says the bridge was built by a Chinese contractor, and paid for jointly by Senegal and by China, through the Export-Import Bank of China.
Mr Sall thanked China for its unbroken help in providing Senegal with the infrastructure envisaged by the national plan to revitalise the country, Xinhua says.