Julio Cesar Chavez Jr. was deported from the United States to Mexico ... but the star boxer isn't roaming free in his home country -- instead, he's cooling his heels in a jail cell after American authorities turned him over to officials south of the border.
Chavez Jr. was deported from an undisclosed location in America on August 18 ... after 46 days in U.S. custody. Shortly before noon, he was transferred to a high-security prison in Hermosillo, Sonora.
JCC Jr.