43 U.S.C. § 1599
Definitions
As used in this subchapter—
(a)
all terms that are defined in the Colorado River Compact shall have the meanings therein defined;
(b)
“Colorado River Basin States” means the States of Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming.
( Pub. L. 93–320, title II, § 209 , June 24, 1974 , 88 Stat. 275 .)