Willis Thrall (1800 - 1884) was an American map publisher based in Hartford Connecticut during the early part of the 19th century. Thrall published numerous maps and also seems to have opened a tool and rule company in 1844, which he passed on to his son, Edward Thrall, as 'Will Thrall and Son'. No Thrall engravings appear after about 1836, however, the tool company seems to have prospered. Thrall's most important print work was published in conjunction with D. W. Kellogg, with whom his family was associated by marriage.