in 1915, walsh produced part one of "the placenames of westmeath", and abridged version of john o'donovan's 1837 ordnance survey letters for the county. it was part of a projected comprehensive work, and though walsh continually collected material on the subject it remained unfinished at his death. an expanded version was published in 1957 by the dublin institute for advanced studies which was heavily supplemented by walsh's notes and annotations.