Definition of "leag"

I found the hand & three others Indians the rest of the Canoes Camped 2 leags Below

1989, Harry W. Duckworth, The English River Book: A North West Company Journal and Account Book of 1786‎, McGill-Queens, page 19

… from the Illand of flowers beinge ten Leags South weste from ytt.

2000, Harry S. Burrage, Gorges and the Grant of the Province of Maine 1622‎, Heritage Books, page 81

… E [by] S distant six Leags.

2006, Joseph E. Garland, The Fish and the Falcon‎, The History Press, page 156