 His chief works in this area are "The Place-Names of Lancashire" (1922), "English Place-Names in -ing" (1923, new edition 1961), "English River Names" (1928), "Studies on English Place- and Personal Names" (1931), "Studies on English Place-Names" (1936), "Street-Names of the City of London" (1954), "Studies on the Population of Medieval London" (1956), and the monumental "Concise Oxford Dictionary of English Place-Names" (1936, new editions 1940, 1947/51 and the last in 1960).The "Dictionary" remained the standard national reference resource for over 40 years, and is still valuable even though some aspects of Ekwall's methodology and some of his ideas are no longer accepted.Although not a county editor of the survey conducted by the English Place-Name Society (1923-date), his philological advice was often sought and acknowledged by scholars preparing the county volumes, such as Allen Mawer and Frank Stenton.