for land surveying, is so named from Edmund Gunter, its
inventor (1581-1626). It is sixty-six feet long, and divided into one
hundred links. As ten square chains make an acre, it follows that an
acre contains 100,000 square links.
According to Gunter.
According to measurement by Gunter's chain.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894