Upvote:11
Sentinelese people from Andamans Sentineli and the North Sentinel Islanders, are an indigenous people who inhabit North Sentinel Island in the Bay of Bengal in India. They are considered one of the world's last uncontacted peoples.
https://en.wikipedia.org/wiki/Sentinelese
Apart from these, Brazil and New Guinea have some of the largest uncontacted tribes in the world.
https://en.wikipedia.org/wiki/Uncontacted_peoples#New_Guinea
Upvote:14
It doesn't reach the bars in the OP of 200 settlers and 3 centuries, but in case you are interested in a smaller experience, Pitcairn Island was settled in 1790 by 27 people. The community they built remained uncontacted for decades and developed independantly for about half a century.
Upvote:32
The peopling of Hawaii in the 1100s or 1200s may qualify. Drifters or shipwrecks could have arrived in the following centuries (for which see Braden's On the Probability of Pre-1778 Japanese Drifts to Hawaii), but the local culture was seemingly isolated from its Polynesian relatives, with its language and religion diverging significantly. James Cook's arrival in 1778 was novel as no foreign visitors had been seen in living memory.