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Effects of water projects on ungulates in the arid southwestern United States are poorly understood, but there are concerns that such projects will displace native ungulates, influence movements, and increase mortality. One such project, the Hayden-Rhodes Aqueduct (HRA), traverses the habitat of desert mule deer (Odocoileus hemionus crooki) and bighorn sheep (Ovis canadensis) in southcentral Arizona. We contrasted home range size, use of vegetation associations, and frequency of animal locations within 500 m of the HRA for mule deer in the Belmont and Big Horn mountains and for bighorn sheep in the Little Harquahala Mountains during construction (1980-84) and after completion (1989-92) of the HRA. We also examined the distance of ungulates to water catchments to determine if added water catchments attracted them. Home range size and use of vegetation associations did not differ (P > 0.05) between periods for deer and sheep. Deer and sheep were rarely within 500 m of the aqueduct, but frequency of locations less-than-or-equal-to 500 m of the HRA did not differ (P > 0.05) between, during, and after construction of the canal. Female deer were closer (P < 0.05) to water catchments in spring and summer prior to completion of the canal but farther (P < 0.05) from water catchments in summer after completion of the HRA. Bighorn sheep were not attracted to water catchments. Data suggest that the additional water was not important to the deer or sheep populations. The HRA reinforced previously established barriers (i.e., highways, fences, railroads) that fragmented habitat but did not alter use of habitats or movements of desert mule deer or bighorn sheep.