 While working for the U.S. Geodetic Survey, Baldwin completed the first American marine survey of Kodiak and the Aleutian Islands in 1909.From 1910-13, he served as a field officer with the U.S.-Canadian International Boundary Survey.Over the years, Baldwin worked locally as a consulting engineer, where, among other activities, he advised the Kennecott Copper Company and the Copper River and Northwestern Railway.