Altenstadt was part of the Limes, the former border of the Roman Empire, that passes through the town. According to excavations, Altenstadt was a Roman garrison in the first half of the second century.
The first documented mention of Altenstadt took place only in the year 767, which makes Altenstadt the oldest municipality of Upper Hesse.
The Lutheran missionary Georg Heinrich Schwarz was born in Höchst an der Nidder in 1868. He laboured in the Cape Bedford Mission, North Queensland, Australia, for 55 years. The anniversary of his arrival is still celebrated there each year in September and known as Muni Day.