ADAMS-ONÍS TREATY. The Adams-Onís (or Florida) Treaty, signed on February 22, 1819, by John Quincy Adams for the United States and by Louis de Onís for Spain, renounced the United States claim to Texas. It fixed the western boundary of the Louisiana Purchase as beginning at the mouth of the Sabine River and running along its south and west bank to the thirty-second parallel and thence directly north to the Río Roxo, or Red River, "then following the course of the Río Roxo westward to the degree of longitude 100 west from London and 23 from Washington; then, crossing the said Red River, and running thence, by a line due north, to the river Arkansas; thence, following the course of the southern bank of the Arkansas to its source, in latitude 42 north; and thence by that parallel of latitude to the South Sea. The whole being as laid down in Melish's map of the United States" (see MELISH MAP).
William M. Malloy, comp., Treaties, Conventions, International Acts, Protocols and Agreements between the United States of America and Other Powers, 1776–1909 (2 vols., Washington: GPO, 1910).