As part of the plea agreement prosecutors agreed to recommend an 18-month prison sentence.
Branscum was arrested in Piqua in February following an investigation that included postal inspectors and the Miami County Sheriff's Office.
Sheriff Dave Duchak said the investigation was sparked by a tip that several pounds of marijuana would be sent from California to addresses in Piqua and Sidney. The packages were intercepted.
A presentence investigation was ordered and sentencing scheduled Jan. 2.
A charge of conspiracy to commit drug possession against a co-defendant, Taylor Massie, 25, of Houston, is pending.