Colchester mayor Theresa Higgins raised the Commonwealth Flag at Colchester Town Hall and it will fly above the High Street for a week.
Surrounded by residents and guests, Mrs Higgins read out a personal message from Kamalesh Sharma, Commonwealth Secretary-General, and a Commonwealth Affirmation.
The celebrations included a Fairtrade breakfast at the town hall where 56 people dropped in for Fairtrade muesli, toast and jam, bananas, tea and coffee courtesy of the East of England Co-op.
After the flag-raising, groups including African Families in the UK, hashtag4biz and the Colchester Fairtrade Town Steering Group as well as invited guests to find out more about the Commonwealth.
The drop-in morning featured food, fashion, artefacts and information from some of the 53 member countries.
Rachel Walton, co-founder of African Families in the UK, represented Kenya.
She said: “It was a really good way of integrating and bringing the Commonwealth countries together.
“Some of our countries were colonised by the British and we love this country. This event was a really good way of feeling like we belong.”
Don Manhire, secretary of Colchester’s Fairtrade Town Steering Group, said: “The breakfast was partly to celebrate ten years as a group and partly to celebrate the annual Fairtrade Fortnight.
“As a group, we are trying to increase people’s awareness of the need to buy Fairtrade products.
“It gives a secure price to growers of crops like coffee and tea in poorer countries.”