Kimberly Williams appeals the denial of her motion requesting that the district court 1 recommend to the Bureau of Prisons that she be allowed to serve the last 6 months of her 18-month prison sentence at a community correction center. We dismiss the appeal as moot, because Williams was released from custody on March 2, 2007. See Mills v. Green, 159 U.S. 651, 653, 16 S.Ct. 132, 40 L.Ed. 293 (1895) (when event occurs during pendency of appeal that renders it impossible for court, if it should decide case in favor of plaintiff, to grant effective relief, court will dismiss appeal as moot).