The flag of Saint Kitts and Nevis consists of a yellow-edged black band containing two white stars that divide diagonally from the lower hoist-side corner, with a green upper triangle and red lower triangle. Adopted in 1983 to replace the flag of Saint Christopher-Nevis-Anguilla, it has been the flag of the Federation of Saint Kitts and Nevis since the country gained independence that year. Although the flag utilises the colours of the Pan-Africanist movement, the symbolism behind them is interpreted differently.[1] The three islands later became part of the West Indies Federation in 1958; after this dissolved four years later, they were granted the status of the associate state as Saint Christopher-Nevis-Anguilla.[2] However, Anguilla decided to secede from the federation in 1969,[3] owing to fears that their population, which was already small, would be further marginalised in parliament.[2] This was eventually formalised in 1980,[3] and a new flag for the remaining parts of the federation was needed, since the symbolism of the previous flag centred on the concept of a union of three.

https://en.wikipedia.org/wiki/Flag_of_Saint_Kitts_and_Nevis