American interest in and knowledge of religion in India began before Americans imagined Hinduism as a coherent world religion. In the eighteenth and nineteenth century, Americans used a variety of terms to describe, represent, and imagine the religious culture of India: Gentoos, Hindoos, religion of the Hindoos, Hindoo religion, Brahmanism, heathenism, and paganism. Each term meant different things to different writers at different times. But there was no Hinduism, a world religion originating in India and comparable to others, in America prior to the late nineteenth century. Americans read and wrote about “Hindoos” and “Hindoo religion,” something altogether different from Hindus and Hinduism. This article analyzes two examples of American representations of Hindoo religion before Hinduism. First, it examines American missionary reports about “Hindoo heathenism” written by American Board of Commissioners for Foreign Missions missionaries and published in American missionary journals in the early nineteenth century. Second, it examines the Unitarian interest in Rammohun Roy and his growing popularity in New England during the 1820s and 1830s. Unitarian interest in Roy and ABCFM missionary reports exemplify the ways Protestant questions and interests shaped the American understanding of religions and the eventual construction of “world religions” such as Hinduism to suit American Protestant concerns.