Ronald Washington pleaded guilty to conspiring to distribute and possess with intent to distribute 50 grams or more of a mixture or substance containing cocaine base, in violation of 21 U.S.C. §§ 841(a)(1), 841 (b)(1)(A)(iii), and 846, and 18 U.S.C. § 2. At sentencing, the district court 1 granted Washington’s motion for a downward departure, reducing his criminal history from Category IV to Category III, and sentenced him to 135 months imprisonment and 5 years supervised release.

On appeal, Washington argues that departure to Category II was warranted. We reject this argument because the extent of the district court’s downward departure is unreviewable, see United States v. Dutcher, 8 F.3d 11, 12 (8th Cir. 1993), and Washington agreed in his written plea agreement that his prison term would be between 121-151 months, see United States v. Nguyen, 46 F.3d 781, 783 (8th Cir. 1995). Accordingly, we affirm.