When Niels Andersen was born in 1717, in Hårby, Odense, Denmark, his father, Anders, was 32 and his mother, Mrs Anders, was 28. He married Martha Rasmussen on 21 November 1749, in Hårby, Odense, Denmark. They were the parents of at least 6 sons and 4 daughters. He died on 5 October 1789, in Sønder Broby, Broby, Fyn, Denmark, at the age of 72.